/* ============================================
   AMPLI DESIGN SYSTEM
   A premium tech media network aesthetic
   ============================================ */

/* Font Imports */
@import url('https://api.fontshare.com/v2/css?f[]=clash-display@200,300,400,500,600,700&f[]=satoshi@300,400,500,700&display=swap');

/* ============================================
   CSS VARIABLES
   ============================================ */
:root {
    /* Brand Colors - Ampli Brand Palette */
    --brand-yellow: #FFC53E;          /* Accent Yellow */
    --brand-purple: #7F7EFF;          /* Accent Purple */
    --brand-green: #00916E;           /* Primary Green */
    --brand-primary: #00916E;         /* Primary Green (alias) */
    --brand-white: #f5f5f0;           /* BG Light */
    --brand-black: #1a1a1a;           /* Text Dark */

    /* Background Colors */
    --bg-primary: #08070d;
    --bg-secondary: #0f0e16;
    --bg-tertiary: #18161f;
    --bg-card: rgba(255, 255, 255, 0.02);
    --bg-card-hover: rgba(255, 255, 255, 0.05);

    /* Text Colors */
    --text-primary: #f5f5f0;
    --text-secondary: #a8a8b8;
    --text-muted: #5a5a6e;

    /* Unified Signal Theme - Using Brand Colors */
    --signal-cyan: var(--brand-purple);
    --signal-blue: var(--brand-purple);
    --signal-electric: var(--brand-green);
    --channel-primary: var(--brand-purple);
    --channel-secondary: var(--brand-green);
    --channel-glow: rgba(127, 126, 255, 0.4);

    /* Berlin Newsletter - Yellow accent */
    --berlin-primary: var(--brand-yellow);
    --berlin-secondary: #E6B335;
    --berlin-glow: rgba(255, 197, 62, 0.35);

    /* Vibe AI Newsletter - Purple accent */
    --ai-primary: var(--brand-purple);
    --ai-secondary: #6B6AE6;
    --ai-glow: rgba(127, 126, 255, 0.35);

    /* Utility */
    --border-color: rgba(255, 255, 255, 0.08);
    --border-color-hover: rgba(255, 255, 255, 0.15);

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;
    --space-5xl: 8rem;

    /* Layout */
    --max-width: 1280px;
    --header-height: 80px;

    /* Typography */
    --font-display: 'Clash Display', sans-serif;
    --font-body: 'Satoshi', sans-serif;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.25s ease;
    --transition-slow: 0.4s ease;

    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --radius-full: 100px;
}

/* Berlin Channel Theme */
[data-channel="berlin"] {
    --channel-primary: var(--berlin-primary);
    --channel-secondary: var(--berlin-secondary);
    --channel-glow: var(--berlin-glow);
}

/* AI Channel Theme */
[data-channel="ai"] {
    --channel-primary: var(--ai-primary);
    --channel-secondary: var(--ai-secondary);
    --channel-glow: var(--ai-glow);
}

/* ============================================
   RESET & BASE
   ============================================ */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-body);
    font-size: 16px;
    font-weight: 400;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg-primary);
    overflow-x: hidden;
}

/* Noise texture overlay */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 9999;
    opacity: 0.025;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

img, video {
    max-width: 100%;
    height: auto;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

ul, ol {
    list-style: none;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: 600;
    line-height: 1.1;
    letter-spacing: -0.02em;
}

h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); }
h2 { font-size: clamp(2rem, 4vw, 3rem); }
h3 { font-size: clamp(1.5rem, 3vw, 2rem); }
h4 { font-size: clamp(1.25rem, 2vw, 1.5rem); }

p {
    color: var(--text-secondary);
    max-width: 65ch;
}

.text-gradient {
    background: linear-gradient(135deg, var(--signal-cyan), var(--signal-electric));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.text-channel {
    color: var(--channel-primary);
}

.label {
    font-family: var(--font-body);
    font-size: 0.75rem;
    font-weight: 500;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
}

/* ============================================
   LAYOUT
   ============================================ */
.container {
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

@media (min-width: 768px) {
    .container {
        padding: 0 var(--space-2xl);
    }
}

.section {
    padding: var(--space-4xl) 0;
}

@media (min-width: 768px) {
    .section {
        padding: var(--space-5xl) 0;
    }
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
}

.section-header .label {
    margin-bottom: var(--space-md);
    display: block;
}

.section-header h2 {
    margin-bottom: var(--space-md);
}

.section-header p {
    margin: 0 auto;
    font-size: 1.125rem;
}

/* ============================================
   HEADER & NAVIGATION
   ============================================ */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    height: var(--header-height);
    display: flex;
    align-items: center;
    background: linear-gradient(to bottom, var(--bg-primary), transparent);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
}

/* Logo */
.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    transition: opacity var(--transition-fast);
}

.logo:hover {
    opacity: 0.8;
}

.logo-icon {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.logo-icon svg {
    width: 100%;
    height: 100%;
}

/* Desktop Navigation */
.nav-desktop {
    display: none;
    align-items: center;
    gap: var(--space-xl);
}

@media (min-width: 768px) {
    .nav-desktop {
        display: flex;
    }
}

.nav-link {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link:hover {
    color: var(--text-primary);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--channel-primary);
    transition: width var(--transition-base);
}

.nav-link:hover::after {
    width: 100%;
}

/* Newsletter Dropdown */
.nav-dropdown {
    position: relative;
}

.nav-dropdown-trigger {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: color var(--transition-fast);
}

.nav-dropdown-trigger:hover {
    color: var(--text-primary);
}

.nav-dropdown-trigger svg {
    width: 16px;
    height: 16px;
    transition: transform var(--transition-fast);
}

.nav-dropdown:hover .nav-dropdown-trigger svg {
    transform: rotate(180deg);
}

.nav-dropdown-menu {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(8px);
    min-width: 220px;
    padding: var(--space-sm);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.nav-dropdown:hover .nav-dropdown-menu {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.nav-dropdown-item {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md);
    border-radius: var(--radius-md);
    transition: background var(--transition-fast);
}

.nav-dropdown-item:hover {
    background: var(--bg-card-hover);
}

.nav-dropdown-icon {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-tertiary);
    border-radius: var(--radius-sm);
    font-size: 1.25rem;
}

.nav-dropdown-icon svg {
    width: 20px;
    height: 20px;
    color: var(--text-secondary);
}

.nav-dropdown-text {
    flex: 1;
}

.nav-dropdown-text strong {
    display: block;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-primary);
}

.nav-dropdown-text span {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* Mobile Menu Button */
.menu-toggle {
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: var(--space-sm);
    cursor: pointer;
}

@media (min-width: 768px) {
    .menu-toggle {
        display: none;
    }
}

.menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all var(--transition-fast);
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile Navigation */
.nav-mobile {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--bg-primary);
    padding: var(--space-xl);
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
    transform: translateX(100%);
    transition: transform var(--transition-slow);
    z-index: 999;
}

.nav-mobile.active {
    transform: translateX(0);
}

.nav-mobile a {
    font-size: 1.5rem;
    font-family: var(--font-display);
    font-weight: 500;
    color: var(--text-primary);
    padding: var(--space-md) 0;
    border-bottom: 1px solid var(--border-color);
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: 0.875rem 1.75rem;
    font-family: var(--font-body);
    font-size: 0.9rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    transition: all var(--transition-base);
    white-space: nowrap;
}

.btn svg {
    width: 18px;
    height: 18px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--signal-cyan), var(--signal-electric));
    color: var(--brand-black);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0, 217, 255, 0.4), 0 8px 30px rgba(0, 255, 204, 0.3);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-color-hover);
}

.btn-channel {
    background: var(--channel-primary);
    color: var(--bg-primary);
}

.btn-channel:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px var(--channel-glow);
}

.btn-outline {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-outline:hover {
    border-color: var(--channel-primary);
    color: var(--channel-primary);
}

.btn-sm {
    padding: 0.625rem 1.25rem;
    font-size: 0.85rem;
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1rem;
}

/* ============================================
   CARDS
   ============================================ */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    transition: all var(--transition-base);
}

.card:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-color-hover);
    transform: translateY(-4px);
}

/* Newsletter Card */
.newsletter-card {
    position: relative;
    overflow: hidden;
    cursor: pointer;
}

.newsletter-card::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, var(--card-accent, var(--channel-primary)) 0%, transparent 60%);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.newsletter-card:hover::before {
    opacity: 0.08;
}

.newsletter-card:hover {
    border-color: var(--card-accent, var(--channel-primary));
}

.newsletter-card-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: var(--space-lg);
    position: relative;
    z-index: 1;
}

.newsletter-card-icon {
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1.5rem;
}

.newsletter-card-icon svg {
    width: 100%;
    height: 100%;
    padding: 8px;
    color: var(--card-accent, var(--channel-primary));
}

.newsletter-card-badge {
    font-family: var(--font-body);
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    padding: 0.375rem 0.75rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--card-accent, var(--channel-primary));
    border-radius: var(--radius-full);
    color: var(--card-accent, var(--channel-primary));
}

.newsletter-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--space-sm);
    position: relative;
    z-index: 1;
}

.newsletter-card p {
    font-size: 0.95rem;
    margin-bottom: var(--space-lg);
    position: relative;
    z-index: 1;
}

.newsletter-card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    margin-bottom: var(--space-lg);
    position: relative;
    z-index: 1;
}

.tag {
    font-size: 0.75rem;
    font-weight: 500;
    padding: 0.5rem 0.875rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    color: var(--text-secondary);
}

.newsletter-card-cta {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    font-weight: 600;
    color: var(--card-accent, var(--channel-primary));
    position: relative;
    z-index: 1;
    transition: gap var(--transition-base);
}

.newsletter-card:hover .newsletter-card-cta {
    gap: var(--space-md);
}

.newsletter-card-cta svg {
    width: 18px;
    height: 18px;
}

/* Issues Grid Container */
.issues-grid {
    display: grid;
    gap: var(--space-xl);
    grid-template-columns: 1fr;
}

@media (min-width: 768px) {
    .issues-grid {
        gap: var(--space-2xl);
    }
}

/* Issue Card */
.issue-card {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
    position: relative;
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: all var(--transition-normal);
}

.issue-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, var(--channel-glow) 0%, transparent 50%);
    opacity: 0;
    transition: opacity var(--transition-normal);
    pointer-events: none;
    border-radius: var(--radius-lg);
}

.issue-card:hover::before {
    opacity: 0.08;
}

.issue-card:hover {
    border-color: var(--channel-primary);
    box-shadow: 0 0 30px var(--channel-glow);
    transform: translateY(-2px);
}

@media (min-width: 640px) {
    .issue-card {
        flex-direction: row;
        align-items: flex-start;
        gap: var(--space-xl);
    }
}

/* Broadcast Signal Image Container */
.issue-card-image {
    width: 100%;
    aspect-ratio: 1 / 1;
    background: linear-gradient(135deg, var(--bg-tertiary) 0%, var(--bg-secondary) 100%);
    border-radius: var(--radius-lg);
    overflow: hidden;
    flex-shrink: 0;
    position: relative;
    border: 1px solid rgba(255, 255, 255, 0.08);
    box-shadow: inset 0 0 20px rgba(0, 0, 0, 0.3);
}

.issue-card-image::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        repeating-linear-gradient(
            0deg,
            transparent 0px,
            rgba(255, 255, 255, 0.02) 1px,
            transparent 2px,
            transparent 4px
        );
    pointer-events: none;
    opacity: 0.5;
}

@media (min-width: 640px) {
    .issue-card-image {
        width: 140px;
        aspect-ratio: 1 / 1;
    }
}

/* Logo Display - Contained Fit (No Cropping) */
.issue-card-image img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: 16px;
    transition: all var(--transition-slow);
}

.issue-card:hover .issue-card-image img {
    transform: scale(1.08);
    filter: brightness(1.1);
}

/* Signal Pulse Effect on Hover */
@keyframes signal-pulse {
    0%, 100% {
        box-shadow:
            inset 0 0 20px rgba(0, 0, 0, 0.3),
            0 0 0 0 var(--channel-glow);
    }
    50% {
        box-shadow:
            inset 0 0 20px rgba(0, 0, 0, 0.3),
            0 0 20px 4px var(--channel-glow);
    }
}

.issue-card:hover .issue-card-image {
    animation: signal-pulse 2s ease-in-out infinite;
    border-color: var(--channel-primary);
}

.issue-card-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: var(--space-sm);
}

.issue-card-date {
    font-family: 'Courier New', monospace;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    text-transform: uppercase;
    opacity: 0.7;
}

.issue-card h4 {
    font-size: 1.15rem;
    line-height: 1.4;
    margin-bottom: 0;
    transition: color var(--transition-fast);
    font-weight: 600;
}

.issue-card:hover h4 {
    color: var(--signal-cyan);
}

.issue-card p {
    font-size: 0.9rem;
    line-height: 1.6;
    color: var(--text-secondary);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* ============================================
   BERLIN CROSS-PROMOTION SECTION
   ============================================ */

/* Section Background */
.berlin-promo-section {
    background: linear-gradient(135deg,
        rgba(0, 217, 255, 0.05) 0%,
        var(--bg-secondary) 40%,
        var(--bg-secondary) 60%,
        rgba(0, 149, 255, 0.05) 100%
    );
    position: relative;
    overflow: hidden;
}

.berlin-promo-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        repeating-linear-gradient(
            0deg,
            transparent 0px,
            rgba(0, 217, 255, 0.02) 1px,
            transparent 2px,
            transparent 4px
        );
    pointer-events: none;
}

/* Main Container */
.berlin-promo {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
    align-items: center;
    background: linear-gradient(135deg,
        rgba(0, 217, 255, 0.1) 0%,
        rgba(0, 149, 255, 0.05) 100%
    );
    border: 1px solid rgba(0, 217, 255, 0.2);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
    position: relative;
    overflow: hidden;
}

.berlin-promo::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(
        circle at 20% 50%,
        rgba(0, 217, 255, 0.15) 0%,
        transparent 60%
    );
    pointer-events: none;
}

@media (min-width: 768px) {
    .berlin-promo {
        grid-template-columns: 200px 1fr auto;
        padding: var(--space-2xl) var(--space-3xl);
    }
}

/* ============================================
   BERLIN SKYLINE ILLUSTRATION
   ============================================ */

.berlin-skyline {
    position: relative;
    width: 100%;
    height: 120px;
    display: flex;
    align-items: flex-end;
    justify-content: center;
    gap: 12px;
}

@media (min-width: 768px) {
    .berlin-skyline {
        height: 140px;
    }
}

/* TV Tower (Fernsehturm) */
.skyline-tv-tower {
    position: absolute;
    left: 30px;
    bottom: 0;
    width: 8px;
    height: 100px;
    background: linear-gradient(180deg,
        rgba(0, 217, 255, 0.6) 0%,
        rgba(0, 217, 255, 0.9) 100%
    );
    border-radius: 4px 4px 0 0;
    animation: tower-glow 3s ease-in-out infinite;
}

.tower-sphere {
    position: absolute;
    top: 20px;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 20px;
    background: radial-gradient(
        circle,
        rgba(0, 217, 255, 0.9) 0%,
        rgba(0, 217, 255, 0.6) 100%
    );
    border-radius: 50%;
    box-shadow:
        0 0 20px rgba(0, 217, 255, 0.6),
        inset 0 0 10px rgba(255, 255, 255, 0.3);
}

.tower-antenna {
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 25px;
    background: linear-gradient(180deg,
        rgba(0, 217, 255, 0.9) 0%,
        transparent 100%
    );
}

@keyframes tower-glow {
    0%, 100% {
        filter: brightness(1);
        box-shadow: 0 0 20px rgba(0, 217, 255, 0.4);
    }
    50% {
        filter: brightness(1.3);
        box-shadow: 0 0 40px rgba(0, 217, 255, 0.8);
    }
}

/* Brandenburg Gate */
.skyline-gate {
    position: absolute;
    right: 30px;
    bottom: 0;
    width: 60px;
    height: 70px;
    display: flex;
    justify-content: space-between;
    align-items: flex-end;
}

.gate-column {
    width: 8px;
    height: 60px;
    background: linear-gradient(180deg,
        rgba(0, 149, 255, 0.7) 0%,
        rgba(0, 217, 255, 0.9) 100%
    );
    border-radius: 2px 2px 0 0;
}

.gate-arch {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 20px;
    border: 3px solid rgba(0, 217, 255, 0.8);
    border-bottom: none;
    border-radius: 30px 30px 0 0;
}

/* City Buildings */
.skyline-buildings {
    display: flex;
    align-items: flex-end;
    gap: 8px;
    height: 100%;
}

.building {
    width: 20px;
    height: var(--height, 60px);
    background: linear-gradient(180deg,
        rgba(0, 149, 255, 0.3) 0%,
        rgba(0, 217, 255, 0.5) 100%
    );
    border: 1px solid rgba(0, 217, 255, 0.3);
    border-bottom: none;
    border-radius: 2px 2px 0 0;
    position: relative;
    opacity: 0.8;
    animation: building-fade 4s ease-in-out infinite;
}

.building:nth-child(1) { animation-delay: 0s; }
.building:nth-child(2) { animation-delay: 0.5s; }
.building:nth-child(3) { animation-delay: 1s; }
.building:nth-child(4) { animation-delay: 1.5s; }
.building:nth-child(5) { animation-delay: 2s; }

@keyframes building-fade {
    0%, 100% { opacity: 0.6; }
    50% { opacity: 0.9; }
}

/* Skyline Glow Base */
.skyline-glow {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 30px;
    background: linear-gradient(180deg,
        transparent 0%,
        rgba(0, 217, 255, 0.2) 100%
    );
    filter: blur(10px);
}

/* ============================================
   CONTENT & CTA
   ============================================ */

.berlin-promo-content {
    text-align: center;
}

@media (min-width: 768px) {
    .berlin-promo-content {
        text-align: left;
    }
}

.berlin-promo-content h3 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
    line-height: 1.2;
}

.berlin-promo-content p {
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-secondary);
    margin: 0;
}

.berlin-promo-cta {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    background: linear-gradient(135deg, var(--signal-cyan), var(--signal-blue));
    color: var(--brand-black);
    font-weight: 600;
    font-size: 1rem;
    border-radius: var(--radius-lg);
    text-decoration: none;
    transition: all var(--transition-normal);
    white-space: nowrap;
    box-shadow: 0 4px 20px rgba(0, 217, 255, 0.3);
}

.berlin-promo-cta svg {
    width: 20px;
    height: 20px;
    transition: transform var(--transition-fast);
}

.berlin-promo-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0, 217, 255, 0.5);
}

.berlin-promo-cta:hover svg {
    transform: translateX(4px);
}

/* ============================================
   AI CROSS-PROMOTION SECTION
   ============================================ */

/* Section Background */
.ai-promo-section {
    background: linear-gradient(135deg,
        rgba(0, 149, 255, 0.05) 0%,
        var(--bg-secondary) 40%,
        var(--bg-secondary) 60%,
        rgba(0, 217, 255, 0.05) 100%
    );
    position: relative;
    overflow: hidden;
}

.ai-promo-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        repeating-linear-gradient(
            45deg,
            transparent 0px,
            rgba(0, 149, 255, 0.01) 1px,
            transparent 2px,
            transparent 8px
        );
    pointer-events: none;
}

/* Main Container */
.ai-promo {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-2xl);
    align-items: center;
    background: linear-gradient(135deg,
        rgba(0, 149, 255, 0.1) 0%,
        rgba(0, 217, 255, 0.05) 100%
    );
    border: 1px solid rgba(0, 149, 255, 0.2);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
    position: relative;
    overflow: hidden;
}

.ai-promo::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(
        circle at 20% 50%,
        rgba(0, 149, 255, 0.15) 0%,
        transparent 60%
    );
    pointer-events: none;
}

@media (min-width: 768px) {
    .ai-promo {
        grid-template-columns: 200px 1fr auto;
        padding: var(--space-2xl) var(--space-3xl);
    }
}

/* ============================================
   AI NETWORK VISUALIZATION
   ============================================ */

.ai-network {
    position: relative;
    width: 100%;
    height: 140px;
}

/* Network Nodes */
.network-node {
    position: absolute;
    width: 12px;
    height: 12px;
    background: radial-gradient(
        circle,
        rgba(0, 149, 255, 1) 0%,
        rgba(0, 149, 255, 0.6) 100%
    );
    border-radius: 50%;
    box-shadow:
        0 0 20px rgba(0, 149, 255, 0.8),
        inset 0 0 5px rgba(255, 255, 255, 0.5);
    animation: node-pulse 2s ease-in-out infinite;
}

.network-node.large {
    width: 20px;
    height: 20px;
    animation: node-pulse-large 2s ease-in-out infinite;
}

.network-node:nth-child(1) { animation-delay: 0s; }
.network-node:nth-child(2) { animation-delay: 0.4s; }
.network-node:nth-child(3) { animation-delay: 0.8s; }
.network-node:nth-child(4) { animation-delay: 1.2s; }
.network-node:nth-child(5) { animation-delay: 1.6s; }

@keyframes node-pulse {
    0%, 100% {
        transform: scale(1);
        box-shadow:
            0 0 20px rgba(0, 149, 255, 0.6),
            inset 0 0 5px rgba(255, 255, 255, 0.5);
    }
    50% {
        transform: scale(1.2);
        box-shadow:
            0 0 30px rgba(0, 149, 255, 1),
            inset 0 0 8px rgba(255, 255, 255, 0.8);
    }
}

@keyframes node-pulse-large {
    0%, 100% {
        transform: scale(1);
        box-shadow:
            0 0 30px rgba(0, 149, 255, 0.8),
            inset 0 0 8px rgba(255, 255, 255, 0.5);
    }
    50% {
        transform: scale(1.15);
        box-shadow:
            0 0 45px rgba(0, 149, 255, 1),
            inset 0 0 12px rgba(255, 255, 255, 0.8);
    }
}

/* Network Connections */
.network-connections {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.connection-line {
    stroke: rgba(0, 149, 255, 0.4);
    stroke-width: 1.5;
    stroke-dasharray: 4 2;
    animation: dash-flow 3s linear infinite;
}

@keyframes dash-flow {
    to {
        stroke-dashoffset: -20;
    }
}

/* Network Pulse Effect */
.network-pulse {
    position: absolute;
    top: 35%;
    left: 70%;
    width: 40px;
    height: 40px;
    transform: translate(-50%, -50%);
    border-radius: 50%;
    background: rgba(0, 149, 255, 0.2);
    animation: pulse-expand 2s ease-out infinite;
}

@keyframes pulse-expand {
    0% {
        width: 20px;
        height: 20px;
        opacity: 1;
    }
    100% {
        width: 80px;
        height: 80px;
        opacity: 0;
    }
}

/* ============================================
   AI PROMO CONTENT & CTA
   ============================================ */

.ai-promo-content {
    text-align: center;
}

@media (min-width: 768px) {
    .ai-promo-content {
        text-align: left;
    }
}

.ai-promo-content h3 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
    line-height: 1.2;
}

.ai-promo-content p {
    font-size: 1rem;
    line-height: 1.6;
    color: var(--text-secondary);
    margin: 0;
}

.ai-promo-cta {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    background: linear-gradient(135deg, var(--signal-blue), var(--ai-primary));
    color: var(--brand-white);
    font-weight: 600;
    font-size: 1rem;
    border-radius: var(--radius-lg);
    text-decoration: none;
    transition: all var(--transition-normal);
    white-space: nowrap;
    box-shadow: 0 4px 20px rgba(0, 149, 255, 0.3);
}

.ai-promo-cta svg {
    width: 20px;
    height: 20px;
    transition: transform var(--transition-fast);
}

.ai-promo-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0, 149, 255, 0.5);
}

.ai-promo-cta:hover svg {
    transform: translateX(4px);
}

/* ============================================
   FORMS
   ============================================ */
.form-group {
    margin-bottom: var(--space-lg);
}

.form-label {
    display: block;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: var(--space-md) var(--space-lg);
    font-family: var(--font-body);
    font-size: 1rem;
    color: var(--text-primary);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--channel-primary);
    box-shadow: 0 0 0 3px var(--channel-glow);
}

.form-input::placeholder,
.form-textarea::placeholder {
    color: var(--text-muted);
}

.form-textarea {
    min-height: 150px;
    resize: vertical;
}

/* Substack Embed */
.substack-embed {
    width: 100%;
    border-radius: var(--radius-md);
    overflow: hidden;
}

.substack-embed iframe {
    width: 100%;
    min-height: 150px;
}

/* Subscribe Form */
.subscribe-form {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

@media (min-width: 480px) {
    .subscribe-form.inline {
        flex-direction: row;
    }

    .subscribe-form.inline .form-input {
        flex: 1;
    }
}

/* Channel Checkboxes */
.channel-select {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-md);
}

.channel-checkbox {
    display: none;
}

.channel-label {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.channel-label:hover {
    border-color: var(--border-color-hover);
}

.channel-checkbox:checked + .channel-label {
    border-color: var(--channel-primary);
    background: rgba(255, 255, 255, 0.03);
}

.channel-check {
    width: 22px;
    height: 22px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.channel-checkbox:checked + .channel-label .channel-check {
    background: var(--channel-primary);
    border-color: var(--channel-primary);
}

.channel-check svg {
    width: 14px;
    height: 14px;
    opacity: 0;
    color: var(--bg-primary);
    transition: opacity var(--transition-fast);
}

.channel-checkbox:checked + .channel-label .channel-check svg {
    opacity: 1;
}

.channel-label-icon {
    font-size: 1.25rem;
}

.channel-label-text {
    font-weight: 500;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
    padding: var(--space-4xl) 0 var(--space-xl);
    border-top: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.footer-grid {
    display: grid;
    gap: var(--space-2xl);
    margin-bottom: var(--space-3xl);
}

@media (min-width: 768px) {
    .footer-grid {
        grid-template-columns: 2fr 1fr 1fr 1fr;
    }
}

.footer-brand {
    max-width: 280px;
}

.footer-brand .logo {
    margin-bottom: var(--space-md);
}

.footer-brand p {
    font-size: 0.9rem;
}

.footer-column h4 {
    font-family: var(--font-body);
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-lg);
    color: var(--text-primary);
}

.footer-column a {
    display: block;
    font-size: 0.9rem;
    color: var(--text-secondary);
    padding: var(--space-xs) 0;
    transition: color var(--transition-fast);
}

.footer-column a:hover {
    color: var(--text-primary);
}

.footer-bottom {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--border-color);
}

@media (min-width: 640px) {
    .footer-bottom {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
    }
}

.footer-copyright {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.footer-social {
    display: flex;
    gap: var(--space-md);
}

.footer-social a {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.footer-social a:hover {
    background: var(--bg-card-hover);
    color: var(--text-primary);
    transform: translateY(-2px);
}

.footer-social svg {
    width: 18px;
    height: 18px;
}

/* ============================================
   HERO SECTIONS
   ============================================ */
.hero {
    min-height: 70vh;
    display: flex;
    align-items: center;
    padding-top: var(--header-height);
    padding-bottom: var(--space-3xl);
    position: relative;
    overflow: hidden;
}

@media (max-width: 768px) {
    .hero {
        min-height: 70vh;
        padding-top: calc(var(--header-height) + var(--space-2xl));
        padding-bottom: var(--space-2xl);
    }
}

.hero-bg {
    position: absolute;
    inset: 0;
    z-index: -1;
    left: 0;
    top: 0;
}

.hero-gradient {
    position: absolute;
    width: 800px;
    height: 800px;
    border-radius: 50%;
    filter: blur(120px);
    opacity: 0.35;
}

.hero-gradient-1 {
    top: -20%;
    right: -10%;
    background: var(--channel-primary);
}

.hero-gradient-2 {
    bottom: -30%;
    left: -10%;
    background: var(--brand-green);
}

.hero-grid-pattern {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255, 255, 255, 0.015) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255, 255, 255, 0.015) 1px, transparent 1px);
    background-size: 64px 64px;
    mask-image: radial-gradient(ellipse at center, black 20%, transparent 70%);
}

.hero-content {
    display: grid;
    gap: var(--space-3xl);
    align-items: center;
}

@media (max-width: 768px) {
    .hero-content {
        gap: var(--space-xl);
    }
}

@media (min-width: 1024px) {
    .hero-content {
        grid-template-columns: 1fr 1fr;
    }
}

.hero-text {
    max-width: 600px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: 0.5rem 1rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: var(--space-lg);
}

.hero-badge .pulse {
    width: 8px;
    height: 8px;
    background: var(--brand-green);
    border-radius: 50%;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.1); }
}

.hero h1 {
    margin-bottom: var(--space-lg);
}

.hero-description {
    font-size: 1.25rem;
    margin-bottom: var(--space-xl);
}

@media (max-width: 768px) {
    .hero-description {
        font-size: 1.1rem;
        margin-bottom: var(--space-lg);
    }
}

.hero-cta {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-md);
    margin-bottom: var(--space-3xl);
}

@media (max-width: 768px) {
    .hero-cta {
        margin-bottom: var(--space-xl);
    }
}

.hero-stats {
    display: flex;
    gap: var(--space-2xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--border-color);
}

@media (max-width: 768px) {
    .hero-stats {
        gap: var(--space-lg);
        padding-top: var(--space-lg);
        flex-wrap: wrap;
    }
}

.hero-stat-value {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1;
    margin-bottom: var(--space-xs);
}

.hero-stat-label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Signal Visualization */
.hero-visual {
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

@media (max-width: 768px) {
    .hero-visual {
        display: none;
    }
}

.signal-rings {
    position: relative;
    width: 100%;
    max-width: 400px;
    aspect-ratio: 1;
}

.signal-ring {
    position: absolute;
    inset: 0;
    border: 1px solid var(--border-color);
    border-radius: 50%;
    animation: signal-expand 4s ease-out infinite;
}

.signal-ring:nth-child(1) { animation-delay: 0s; }
.signal-ring:nth-child(2) { animation-delay: 1s; }
.signal-ring:nth-child(3) { animation-delay: 2s; }
.signal-ring:nth-child(4) { animation-delay: 3s; }

@keyframes signal-expand {
    0% {
        transform: scale(0.3);
        opacity: 0.6;
    }
    100% {
        transform: scale(1);
        opacity: 0;
    }
}

.signal-core {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 140px;
    height: 140px;
    background: var(--ai-primary);
    border-radius: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 0 80px var(--ai-glow);
    animation: core-glow 3s ease-in-out infinite;
}

@keyframes core-glow {
    0%, 100% {
        box-shadow: 0 0 60px var(--ai-glow);
    }
    50% {
        box-shadow: 0 0 100px var(--ai-glow);
    }
}

.signal-core svg {
    width: 80px;
    height: 80px;
}

/* ============================================
   ANIMATIONS
   ============================================ */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    animation: fadeIn 0.6s ease forwards;
}

.fade-in-delay-1 { animation-delay: 0.1s; }
.fade-in-delay-2 { animation-delay: 0.2s; }
.fade-in-delay-3 { animation-delay: 0.3s; }
.fade-in-delay-4 { animation-delay: 0.4s; }

@keyframes fadeIn {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Reveal on scroll */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ============================================
   UTILITIES
   ============================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mx-auto { margin-left: auto; margin-right: auto; }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-sm { gap: var(--space-sm); }
.gap-md { gap: var(--space-md); }
.gap-lg { gap: var(--space-lg); }
.gap-xl { gap: var(--space-xl); }

.grid { display: grid; }

.hidden { display: none; }

@media (min-width: 768px) {
    .md\:flex { display: flex; }
    .md\:hidden { display: none; }
    .md\:grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
    .md\:grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
}

@media (min-width: 1024px) {
    .lg\:grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
}

/* ============================================
   SOCIAL PROOF COMPONENTS
   Reusable components for company logos and event galleries
   ============================================ */

/* Event Photo Gallery */
.events-gallery {
    position: relative;
    overflow: hidden;
}

.events-gallery::before {
    content: '';
    position: absolute;
    top: -100px;
    right: -100px;
    width: 400px;
    height: 400px;
    background: var(--berlin-primary);
    filter: blur(200px);
    opacity: 0.08;
    pointer-events: none;
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-sm);
}

@media (min-width: 640px) {
    .gallery-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: var(--space-md);
    }
}

@media (min-width: 1024px) {
    .gallery-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.gallery-item {
    position: relative;
    aspect-ratio: 4/3;
    border-radius: var(--radius-lg);
    overflow: hidden;
    cursor: pointer;
    background: var(--bg-tertiary);
}

.gallery-item::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(to top, rgba(0,0,0,0.4) 0%, transparent 50%);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.gallery-item:hover::after {
    opacity: 1;
}

.gallery-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.gallery-item:hover img {
    transform: scale(1.08);
}

/* Featured gallery items - larger */
.gallery-item.featured {
    grid-column: span 2;
    grid-row: span 2;
    aspect-ratio: 1;
}

@media (max-width: 639px) {
    .gallery-item.featured {
        grid-column: span 2;
        grid-row: span 1;
        aspect-ratio: 16/9;
    }
}

.gallery-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: var(--space-xl);
    color: var(--text-muted);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    background: var(--bg-tertiary);
}

.gallery-placeholder svg {
    width: 48px;
    height: 48px;
    margin-bottom: var(--space-md);
    opacity: 0.5;
}

.gallery-placeholder p {
    font-size: 0.9rem;
    margin: 0;
}

/* Company Logos Carousel */
.company-logos {
    position: relative;
    overflow: hidden;
    margin: 0 auto;
    max-width: 100%;
    padding: var(--space-lg) 0;
}

/* Gradient fade masks for polished edges */
.company-logos::before,
.company-logos::after {
    content: '';
    position: absolute;
    top: 0;
    bottom: 0;
    width: 120px;
    z-index: 2;
    pointer-events: none;
}

.company-logos::before {
    left: 0;
    background: linear-gradient(90deg, var(--bg-secondary) 0%, transparent 100%);
}

.company-logos::after {
    right: 0;
    background: linear-gradient(270deg, var(--bg-secondary) 0%, transparent 100%);
}

.company-logos-track {
    display: flex;
    align-items: center;
    gap: var(--space-2xl);
    width: fit-content;
    animation: slideLogos 40s linear infinite;
}

/* Pause animation on hover for accessibility */
.company-logos:hover .company-logos-track {
    animation-play-state: paused;
}

@keyframes slideLogos {
    0% {
        transform: translateX(0);
    }
    100% {
        transform: translateX(-50%);
    }
}

.company-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    flex-shrink: 0;
    opacity: 0.8;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.company-logo:hover {
    opacity: 1;
    transform: scale(1.15) translateY(-2px);
}

.company-logo img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    border-radius: var(--radius-sm);
}

@media (min-width: 768px) {
    .company-logo {
        width: 64px;
        height: 64px;
    }

    .company-logos-track {
        gap: var(--space-3xl);
    }

    .company-logos::before,
    .company-logos::after {
        width: 160px;
    }
}

/* Respect user motion preferences */
@media (prefers-reduced-motion: reduce) {
    .company-logos-track {
        animation: none;
    }

    .company-logos {
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }
}