/* ============================================
   AIT-USA Landing Page — Design System
   ============================================ */

/* ---------- CSS Variables ---------- */
:root {
    --bg-dark: #0a0a0c;
    --bg-charcoal: #0d0d12;
    --white: #ffffff;
    --white-soft: rgba(255, 255, 255, 0.85);
    --white-dim: rgba(255, 255, 255, 0.5);
    --white-muted: rgba(255, 255, 255, 0.25);
    --accent-cyan: #00e5ff;
    --accent-blue: #2979ff;
    --accent-purple: #7c4dff;
    --glass-bg: rgba(255, 255, 255, 0.04);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-hover: rgba(255, 255, 255, 0.07);
    --glow-cyan: 0 0 40px rgba(0, 229, 255, 0.15);
    --glow-title: 0 0 80px rgba(0, 229, 255, 0.08), 0 0 160px rgba(41, 121, 255, 0.05);
    --radius-sm: 12px;
    --radius-md: 20px;
    --radius-lg: 28px;
    --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --transition-smooth: cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

/* ---------- Reset & Base ---------- */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    font-family: var(--font);
    background: var(--bg-dark);
    color: var(--white);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ---------- Canvas ---------- */
#scene-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
}

/* ---------- Overlay ---------- */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    padding: 2rem 2rem;
    pointer-events: none;
}

.overlay > * {
    pointer-events: auto;
}

/* ---------- Top Bar ---------- */
.top-bar {
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    padding-top: 0.5rem;
    animation: fadeSlideDown 1.2s var(--transition-smooth) both;
    animation-delay: 0.2s;
}

.logo-mark {
    font-size: 1rem;
    color: var(--accent-cyan);
    opacity: 0.6;
    letter-spacing: 4px;
    transition: opacity 0.4s ease;
}

.logo-mark:hover {
    opacity: 1;
}

/* ---------- Hero ---------- */
.hero {
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.2rem;
    margin-top: auto;
    margin-bottom: auto;
    pointer-events: none;
}

.title {
    font-weight: 200;
    font-size: clamp(3.5rem, 10vw, 8rem);
    letter-spacing: 0.35em;
    line-height: 1;
    text-transform: uppercase;
    color: var(--white);
    text-shadow: var(--glow-title);
    animation: fadeScaleIn 1.6s var(--transition-smooth) both;
    animation-delay: 0.4s;
    position: relative;
}

.title::after {
    content: '';
    position: absolute;
    bottom: -12px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--accent-cyan), transparent);
    opacity: 0.4;
    animation: expandLine 2s var(--transition-smooth) both;
    animation-delay: 1.2s;
}

.tagline {
    font-weight: 300;
    font-size: clamp(0.9rem, 2vw, 1.25rem);
    letter-spacing: 0.25em;
    color: var(--white-dim);
    animation: fadeSlideUp 1.4s var(--transition-smooth) both;
    animation-delay: 0.9s;
    margin-top: 1rem;
}

/* ---------- CTA / Glass Card ---------- */
.cta-section {
    width: 100%;
    display: flex;
    justify-content: center;
    animation: fadeSlideUp 1.4s var(--transition-smooth) both;
    animation-delay: 1.3s;
    margin-bottom: 1rem;
}

.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: 2rem 2.5rem;
    max-width: 480px;
    width: 100%;
    text-align: center;
    transition: all 0.5s var(--transition-smooth);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4),
                inset 0 1px 0 rgba(255, 255, 255, 0.05);
}

.glass-card:hover {
    background: var(--glass-hover);
    border-color: rgba(255, 255, 255, 0.12);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5),
                var(--glow-cyan),
                inset 0 1px 0 rgba(255, 255, 255, 0.08);
    transform: translateY(-2px);
}

.cta-text {
    font-size: 0.85rem;
    font-weight: 400;
    color: var(--white-soft);
    letter-spacing: 0.08em;
    margin-bottom: 1.2rem;
}

.input-wrapper {
    display: flex;
    gap: 0;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: all 0.4s ease;
}

.input-wrapper:focus-within {
    border-color: rgba(0, 229, 255, 0.3);
    box-shadow: 0 0 20px rgba(0, 229, 255, 0.06);
}

.email-input {
    flex: 1;
    background: transparent;
    border: none;
    padding: 0.95rem 1.3rem;
    font-family: var(--font);
    font-size: 0.9rem;
    font-weight: 300;
    color: var(--white);
    outline: none;
    letter-spacing: 0.03em;
}

.email-input::placeholder {
    color: var(--white-muted);
    font-weight: 300;
}

.submit-btn {
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue));
    border: none;
    padding: 0.95rem 1.6rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    font-family: var(--font);
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--bg-dark);
    letter-spacing: 0.06em;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.submit-btn:hover {
    filter: brightness(1.15);
    box-shadow: 0 0 24px rgba(0, 229, 255, 0.3);
}

.submit-btn:active {
    transform: scale(0.97);
}

.btn-arrow {
    font-size: 1.05rem;
    transition: transform 0.3s ease;
}

.submit-btn:hover .btn-arrow {
    transform: translateX(3px);
}

.privacy-note {
    font-size: 0.7rem;
    color: var(--white-muted);
    letter-spacing: 0.06em;
    margin-top: 0.9rem;
    font-weight: 300;
}

/* ---------- Footer ---------- */
.bottom-bar {
    width: 100%;
    text-align: center;
    padding-bottom: 0.5rem;
    animation: fadeSlideUp 1.2s var(--transition-smooth) both;
    animation-delay: 1.6s;
}

.copyright {
    font-size: 0.65rem;
    color: var(--white-muted);
    letter-spacing: 0.12em;
    font-weight: 300;
    text-transform: uppercase;
}

/* ============================================
   Animations
   ============================================ */

@keyframes fadeScaleIn {
    0% {
        opacity: 0;
        transform: scale(0.92);
        filter: blur(8px);
    }
    100% {
        opacity: 1;
        transform: scale(1);
        filter: blur(0);
    }
}

@keyframes fadeSlideUp {
    0% {
        opacity: 0;
        transform: translateY(30px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeSlideDown {
    0% {
        opacity: 0;
        transform: translateY(-20px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes expandLine {
    0% {
        width: 0;
        opacity: 0;
    }
    100% {
        width: 60px;
        opacity: 0.4;
    }
}

@keyframes pulseGlow {
    0%, 100% {
        opacity: 0.6;
    }
    50% {
        opacity: 1;
    }
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 768px) {
    .overlay {
        padding: 1.5rem 1.2rem;
    }

    .title {
        letter-spacing: 0.2em;
    }

    .tagline {
        letter-spacing: 0.15em;
    }

    .glass-card {
        padding: 1.5rem 1.5rem;
        border-radius: var(--radius-md);
    }

    .input-wrapper {
        flex-direction: column;
        border-radius: var(--radius-sm);
    }

    .submit-btn {
        justify-content: center;
        padding: 0.85rem 1.3rem;
        border-radius: 0;
    }
}

@media (max-width: 480px) {
    .title {
        letter-spacing: 0.12em;
    }

    .glass-card {
        padding: 1.2rem 1rem;
    }

    .email-input {
        padding: 0.85rem 1rem;
        font-size: 0.85rem;
    }
}