:root {
    /* Brand Neon Palette - Reserved for Accents */
    --td-cyan: #00eaff;
    --td-magenta: #ff00b3;
    --td-yellow: #e8ff00;
    --td-orange: #ff8a00;
    
    /* Deep Backgrounds */
    --td-bg-dark: #090514; /* The main page background */
    --td-panel: #110926;   /* Slightly lighter for cards/panels */
    
    /* Softened UI Elements */
    --td-panel-border: rgba(255, 255, 255, 0.08); /* Very faint structural border */
    --td-text: #e2e2e8; /* Soft off-white to prevent eye strain */
    --td-heading: #ffffff; /* Crisp white for main titles only */
    --td-muted: #9ba1cc;
    --td-yt-red: #ff0000;
    
    /* Interactive Glows ONLY */
    --td-glow-cyan: 0 0 15px rgba(0, 234, 255, 0.25);
    --td-glow-magenta: 0 0 15px rgba(255, 0, 179, 0.25);

    /* Structure */
    --alta-radius: 18px;
    --alta-radius-sm: 12px;
    --alta-max: 1240px;
}

body {
    background: var(--td-bg-dark);
    color: var(--td-text);
}

.alta-library-page {
    width: 100%;
    padding: 32px 20px 80px;
    box-sizing: border-box;
    font-family: inherit; 
}

.alta-library-wrap {
    max-width: var(--alta-max);
    margin: 0 auto;
}

/* Pills & Labels */
.alta-pill {
    display: inline-block;
    background: rgba(0, 234, 255, 0.08);
    color: var(--td-cyan);
    font-size: 0.85rem;
    font-weight: 700;
    padding: 8px 14px;
    border-radius: 999px;
    margin-bottom: 16px;
    border: 1px solid rgba(0, 234, 255, 0.2); /* Subtle cyan hint */
}

.alta-small-label {
    color: var(--td-cyan);
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    font-size: 0.76rem;
    margin-bottom: 10px;
}

/* Panels & Cards Base */
.alta-hero,
.alta-hero-card,
.alta-player-shell,
.alta-access-panel,
.alta-card,
.alta-sponsor-strip,
.alta-som-panel {
    background: var(--td-panel);
    border-radius: var(--alta-radius);
    border: 1px solid var(--td-panel-border);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5); /* Deep shadow */
}

/* Hero Section */
.alta-hero {
    padding: 36px 28px;
    overflow: hidden;
    position: relative;
}

.alta-hero-grid {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 24px;
    align-items: center;
}

.alta-hero h1 {
    font-size: clamp(2rem, 3vw, 3.25rem);
    line-height: 1.05;
    margin: 0 0 14px;
    color: var(--td-heading);
}

.alta-hero p {
    margin: 0 0 18px;
    font-size: 1.06rem;
    line-height: 1.65;
    color: var(--td-text);
    max-width: 60ch;
}

.alta-hero-card {
    padding: 22px;
    background: rgba(255, 255, 255, 0.02); 
}

.alta-hero-card h3 {
    margin: 0 0 8px;
    font-size: 1.1rem;
    color: var(--td-heading);
}

.alta-hero-card p {
    margin: 0 0 12px;
    font-size: 0.96rem;
    line-height: 1.6;
    color: var(--td-muted);
}

/* Buttons */
.alta-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    margin-top: 24px;
}

.alta-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    min-height: 48px;
    padding: 0 18px;
    border-radius: 999px;
    text-decoration: none;
    font-weight: 700;
    border: 2px solid transparent;
    transition: all 0.2s ease;
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    font-size: 0.9rem;
}

.alta-btn-primary {
    background: var(--td-magenta);
    color: #ffffff;
}

.alta-btn-primary:hover {
    background: var(--td-cyan);
    color: var(--td-bg-dark);
    box-shadow: var(--td-glow-cyan);
}

.alta-btn-secondary {
    background: transparent;
    color: var(--td-cyan);
    border-color: var(--td-cyan);
}

.alta-btn-secondary:hover {
    background: var(--td-cyan);
    color: var(--td-bg-dark);
    box-shadow: var(--td-glow-cyan);
}

/* Section Headings */
.alta-section {
    margin-top: 34px;
}

.alta-section-head {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    align-items: end;
    margin-bottom: 18px;
}

.alta-section-head h2 {
    margin: 0;
    font-size: 1.65rem;
    color: var(--td-heading);
}

/* Player Section */
.alta-player-shell {
    overflow: hidden;
}

.alta-player-stage {
    position: relative;
    min-height: 320px;
    background: #000;
    border-bottom: 1px solid var(--td-panel-border);
}

.alta-player-stage iframe,
.alta-player-stage .alta-video-placeholder {
    width: 100%;
    aspect-ratio: 16 / 9;
    min-height: 320px;
    display: block;
    border: 0;
}

/* Dark Placeholder */
.alta-video-placeholder {
    background: var(--td-bg-dark);
    display: grid;
    place-items: center;
    color: var(--td-muted);
    text-align: center;
    padding: 20px;
}

.alta-video-placeholder-inner {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

.alta-video-placeholder-inner svg {
    width: 48px;
    height: 48px;
    opacity: 0.6;
}

.alta-video-placeholder-inner span {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--td-text);
}

.alta-player-meta {
    padding: 26px;
}

.alta-player-meta h3 {
    margin: 0 0 10px;
    font-size: 1.6rem;
    line-height: 1.2;
    color: var(--td-heading);
}

.alta-player-meta p {
    margin: 0 0 18px;
    color: var(--td-muted);
    line-height: 1.7;
}

/* Badges */
.alta-featured-meta {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 14px;
}

.alta-badge {
    display: inline-flex;
    align-items: center;
    background: rgba(232, 255, 0, 0.08); 
    color: var(--td-yellow);
    border: 1px solid rgba(232, 255, 0, 0.2);
    border-radius: 999px;
    padding: 8px 12px;
    font-size: 0.88rem;
    font-weight: 700;
}

.alta-badge.keynote {
    background: rgba(255, 0, 179, 0.08);
    color: var(--td-magenta);
    border-color: rgba(255, 0, 179, 0.2);
}

.alta-next-box {
    margin-top: 18px;
    border-top: 1px solid var(--td-panel-border);
    padding-top: 16px;
    display: flex;
    justify-content: space-between;
    gap: 14px;
    align-items: center;
    flex-wrap: wrap;
}

.alta-next-box small {
    display: block;
    color: var(--td-magenta);
    font-weight: 800;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    margin-bottom: 4px;
}

.alta-next-title {
    font-weight: 700;
    color: var(--td-heading);
}

/* Access Panel & Forms */
.alta-access-panel {
    padding: 24px;
}

.alta-access-panel h3 {
    margin-top: 0;
    margin-bottom: 10px;
    color: var(--td-heading);
}

.alta-access-panel p {
    color: var(--td-muted);
    line-height: 1.65;
}

.alta-form-row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    margin-top: 14px;
}

.alta-input {
    flex: 1 1 280px;
    min-height: 50px;
    border-radius: 14px;
    border: 1px solid var(--td-panel-border);
    padding: 0 16px;
    font-size: 1rem;
    background: var(--td-bg-dark);
    color: var(--td-heading);
    transition: all 0.2s ease;
}

.alta-input:focus {
    outline: none;
    border-color: var(--td-cyan);
    box-shadow: var(--td-glow-cyan);
}

.alta-input::placeholder {
    color: var(--td-muted);
}

.alta-msg {
    margin-top: 12px;
    padding: 12px 14px;
    border-radius: 12px;
    font-weight: 600;
}

.alta-msg.success {
    background: rgba(0, 234, 255, 0.08);
    color: var(--td-cyan);
    border: 1px solid rgba(0, 234, 255, 0.2);
}

.alta-msg.error {
    background: rgba(255, 0, 0, 0.08);
    color: #ff6b6b;
    border: 1px solid rgba(255, 0, 0, 0.2);
}

/* Video Grid */
.alta-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 18px;
}

.alta-card {
    display: flex;
    flex-direction: column;
    height: 100%; /* Forces all cards to stretch and match the tallest card in the row */
    transition: transform 0.2s ease, border-color 0.2s ease;
}

.alta-card:hover {
    transform: translateY(-4px);
    border-color: rgba(255, 255, 255, 0.2); 
}

.alta-card-thumb {
    aspect-ratio: 16 / 9;
    background: #000; 
    position: relative;
    overflow: hidden;
    border-bottom: 1px solid var(--td-panel-border);
}

.alta-card-thumb::before {
    content: "▶";
    position: absolute;
    inset: 0;
    display: grid;
    place-items: center;
    color: var(--td-magenta);
    font-size: 3rem;
    opacity: 0.8;
}

.alta-card-body {
    padding: 18px;
    display: flex;
    flex-direction: column;
    flex-grow: 1; /* Tells the body to expand and fill any empty space */
}

.alta-card-title {
    margin: 0 0 8px;
    font-size: 1.08rem;
    line-height: 1.3;
    color: var(--td-heading);
}

.alta-card-meta {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 12px;
}

.alta-mini {
    font-size: 0.82rem;
    font-weight: 700;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.05);
    color: var(--td-text);
    border-radius: 999px;
    padding: 6px 10px;
}

.alta-card-body p {
    margin: 0 0 16px;
    color: var(--td-muted);
    line-height: 1.6;
    font-size: 0.95rem;
    flex: 1;
    
    /* THE ANTI-CLUTTER MAGIC: Limits text to exactly 3 lines */
    display: -webkit-box;
    -webkit-line-clamp: 4; 
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.alta-card-actions {
    margin-top: auto; /* The magic trick: pushes the button to the very bottom */
    width: 100%;
}

.alta-watch-btn {
    width: 100%;
}

.alta-watch-btn[data-locked="true"] {
    background: transparent;
    border: 2px solid rgba(255, 255, 255, 0.2);
    color: var(--td-text);
}

.alta-watch-btn[data-locked="true"]:hover {
    background: var(--td-orange);
    color: var(--td-bg-dark);
    border-color: var(--td-orange);
    box-shadow: 0 0 15px rgba(255, 138, 0, 0.4);
}

/* --- SPONSOR MARQUEE --- */
.alta-sponsor-strip {
    padding: 24px 0; 
    overflow: hidden; /* Crucial: hides logos scrolling off-screen */
}

.alta-sponsor-strip h3 {
    margin-top: 0;
    margin-bottom: 20px;
    font-size: 1rem;
    color: var(--td-muted);
    padding: 0 20px; /* Keeps heading aligned with the rest of the page */
}

.alta-sponsor-marquee {
    width: 100%;
    display: flex;
    overflow: hidden;
    /* This creates a smooth fade-out effect on the left and right edges */
    mask-image: linear-gradient(to right, transparent, black 10%, black 90%, transparent);
    -webkit-mask-image: linear-gradient(to right, transparent, black 10%, black 90%, transparent);
}

.alta-sponsor-track {
    display: flex;
    gap: 24px;
    padding-left: 24px;
    width: max-content;
    /* 35s is the speed. Lower = faster, Higher = slower */
    animation: scrollMarquee 35s linear infinite; 
}

/* Pauses the scrolling if a user hovers to click a link */
.alta-sponsor-track:hover {
    animation-play-state: paused;
}

.alta-sponsor-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    background: #e2e2e8; /* Soft off-white to make the dark logos pop */
    border-radius: 16px;
    padding: 16px 24px;
    height: 110px; 
    width: 260px; /* Slightly wider to give logos room to breathe */
    flex-shrink: 0; 
    transition: all 0.3s ease;
}

.alta-sponsor-logo:hover {
    background: #ffffff;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.3);
    transform: translateY(-4px);
}

.alta-sponsor-logo img {
    max-height: 65px; /* Logos are significantly larger now */
    max-width: 100%;
    object-fit: contain;
}

/* THE STEPLAB OVERRIDE: Targets Steplab specifically by its label */
.alta-sponsor-logo[aria-label="StepLab"] {
    background: var(--td-panel); /* Uses your existing dark purple theme color */
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.alta-sponsor-logo[aria-label="StepLab"]:hover {
    background: #1a0e3a; 
    border-color: var(--td-cyan);
    box-shadow: var(--td-glow-cyan);
}

@keyframes scrollMarquee {
    0% { transform: translateX(0); }
    /* Shifts exactly half the track to create the infinite loop illusion */
    100% { transform: translateX(calc(-50% - 12px)); } 
}

/* --- ALTA / STORY OF MATHS MARKETING PANEL --- */
.alta-som-panel {
    /* 🎨 ALTA Brand Colors */
    --alta-brand-bg: #164863;         /* darkBlue */
    --alta-brand-text: #ffffff;       /* white */
    --alta-brand-btn-bg: #fada34;     /* yellow */
    --alta-brand-btn-text: #164863;   /* darkBlue text for the yellow button */
    --alta-brand-btn-hover: #427d9d;  /* midBlue for hover state */

    background: var(--alta-brand-bg);
    padding: 48px 32px;
    border-radius: var(--alta-radius);
    text-align: center; /* Centers everything for a billboard effect */
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.6);
    border: 2px solid #427d9d; /* Subtle midBlue border to frame it */
}

.alta-som-logo {
    max-width: 280px; 
    height: auto;
    margin: 0 auto 24px;
    display: block;
}

.alta-som-panel h2 {
    margin-top: 0;
    margin-bottom: 16px;
    color: var(--alta-brand-text);
    font-size: 2rem;
}

.alta-som-panel p {
    margin: 0 auto 28px;
    line-height: 1.75;
    max-width: 65ch; 
    color: var(--alta-brand-text);
    font-size: 1.1rem;
}

/* Custom button specifically for the ALTA panel */
.alta-som-btn {
    background: var(--alta-brand-btn-bg);
    color: var(--alta-brand-btn-text);
    font-weight: 900; /* Makes the button text slightly bolder to stand out */
}

.alta-som-btn:hover {
    background: var(--alta-brand-btn-hover);
    color: #ffffff;
    transform: translateY(-2px);
}
/* Responsive Rules */
@media (max-width: 1100px) {
    .alta-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
    .alta-hero-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 680px) {
    .alta-library-page {
        padding: 18px 14px 60px;
    }
    .alta-hero {
        padding: 24px 18px;
        border-radius: 20px;
    }
    .alta-player-meta,
    .alta-access-panel,
    .alta-som-panel {
        padding: 18px;
    }
    .alta-grid {
        grid-template-columns: 1fr;
    }
    .alta-section-head {
        display: block;
    }
    .alta-actions,
    .alta-form-row {
        flex-direction: column;
    }
    .alta-btn,
    .alta-input {
        width: 100%;
    }
    /* Drops to 2 columns for sponsors on smaller screens */
    .alta-sponsor-logos {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {
    /* Drops to 1 column for sponsors on mobile phones */
    .alta-sponsor-logos {
        grid-template-columns: 1fr;
    }
}