/* ===================================
   DIGITAL BRIDGE 2025 - STYLES
   Dark futuristic theme with animations
   =================================== */

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: #10132a;
    background-image: radial-gradient(
            600px 500px at 15% 10%,
            rgba(108, 186, 255, 0.18),
            transparent 70%
          ),
          radial-gradient(
            800px 600px at 85% 20%,
            rgba(155, 109, 255, 0.18),
            transparent 70%
          ),
          radial-gradient(
            900px 700px at 50% 90%,
            rgba(33, 212, 253, 0.15),
            transparent 70%
          );
    color: #f5f7ff;
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
}

/* Three.js particle canvas */
#particle-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
}

/* Main container */
.container {
    position: relative;
    z-index: 1;
    max-width: 1400px;
    width: 100%;
    margin: 0;
    padding: 2rem 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: flex-start;
}

/* ========== HERO SECTION ========== */
.hero {
    text-align: center;
    padding: 4rem 1rem 3rem;
    margin-bottom: 3rem;
}

.hero-title {
    font-size: clamp(3rem, 8vw, 6rem);
    font-weight: 900;
    background: linear-gradient(90deg, #6cbaff, #9b6dff);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 1rem;
    letter-spacing: -0.03em;
    text-transform: uppercase;
    animation: glow-pulse 3s ease-in-out infinite;
}

@keyframes glow-pulse {
    0%, 100% {
        filter: drop-shadow(0 0 20px rgba(108, 186, 255, 0.5));
    }
    50% {
        filter: drop-shadow(0 0 40px rgba(108, 186, 255, 0.8));
    }
}

.hero-subtitle {
    font-size: clamp(1rem, 2.5vw, 1.5rem);
    font-weight: 300;
    color: #a9afc9;
    letter-spacing: 0.05em;
}

/* ========== LANGUAGE SWITCHER ========== */
.language-switcher {
    position: fixed;
    top: 2rem;
    right: 2rem;
    display: flex;
    gap: 0.5rem;
    z-index: 1000;
    backdrop-filter: blur(10px);
    background: rgba(28, 34, 69, 0.3);
    padding: 0.5rem;
    border-radius: 50px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.language-btn {
    padding: 0.5rem 0.8rem;
    font-size: 0.85rem;
    font-weight: 700;
    background: transparent;
    border: 1px solid transparent;
    color: #a9afc9;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    font-family: 'Inter', sans-serif;
    min-width: 42px;
    text-align: center;
    letter-spacing: 0.05em;
}

.language-btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(108, 186, 255, 0.15);
    transform: translate(-50%, -50%);
    transition: width 0.4s, height 0.4s;
}

.language-btn:hover {
    border-color: rgba(108, 186, 255, 0.3);
    color: #6cbaff;
    background: rgba(108, 186, 255, 0.1);
}

.language-btn:hover::before {
    width: 100px;
    height: 100px;
}

.language-btn.active {
    background: linear-gradient(135deg, rgba(108, 186, 255, 0.25), rgba(155, 109, 255, 0.2));
    border-color: rgba(108, 186, 255, 0.4);
    color: #6cbaff;
    box-shadow: 0 0 15px rgba(108, 186, 255, 0.3);
}

/* ========== DAY TABS ========== */
.day-tabs {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 4rem;
    flex-wrap: wrap;
}

.tab-btn {
    padding: 1rem 2.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    background: rgba(28, 34, 69, 0.8);
    border: 1px solid rgba(255, 255, 255, 0.12);
    color: #a9afc9;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    font-family: 'Inter', sans-serif;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.35);
    display: inline-flex;
    align-items: center;
    gap: 0.8rem; /* a bit more room from the label */
}

/* Date pill inside day button */
.tab-date {
    padding: 0.18rem 0.6rem;
    border-radius: 999px;
    font-size: 0.85rem;
    font-weight: 700;
    line-height: 1;
    color: #6cbaff;
    background: rgba(108, 186, 255, 0.12);
    letter-spacing: 0.02em;
    box-shadow: 0 0 10px rgba(108, 186, 255, 0.18) inset, 0 0 0 rgba(0,0,0,0);
}

/* Hover/active states update the date pill too */
.tab-btn:hover .tab-date {
    background: rgba(108, 186, 255, 0.18);
    box-shadow: 0 0 12px rgba(108, 186, 255, 0.28) inset;
}

.tab-btn.active .tab-date {
    background: linear-gradient(180deg, rgba(108, 186, 255, 0.22), rgba(155, 109, 255, 0.18));
    color: #eaf6ff;
    box-shadow: 0 0 14px rgba(108, 186, 255, 0.35) inset;
}

.tab-btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(108, 186, 255, 0.2);
    transform: translate(-50%, -50%);
    transition: width 0.5s, height 0.5s;
}

.tab-btn:hover {
    border-color: #6cbaff;
    color: #6cbaff;
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(108, 186, 255, 0.3);
}

.tab-btn:hover::before {
    width: 300px;
    height: 300px;
}

.tab-btn.active {
    background: linear-gradient(180deg, rgba(108, 186, 255, 0.14), rgba(155, 109, 255, 0.12));
    border-color: #6cbaff;
    color: #6cbaff;
    box-shadow: 0 0 30px rgba(108, 186, 255, 0.4);
}

/* ========== TIMELINE WRAPPER ========== */
.timeline-wrapper {
    position: relative;
    min-height: 400px;
    margin-bottom: 4rem;
    overflow: visible; /* Allow glow effects to extend beyond */
    padding: 0 1rem;
    width: 100%;
    max-width: 100%;
}

.timeline {
    display: none;
    opacity: 0;
    position: relative;
}

.timeline.active {
    display: block;
    opacity: 1;
}

.timeline-line {
    display: none;
}

/* ========== TIMELINE SESSIONS ========== */
.timeline-sessions {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem 2rem;
    padding: 3rem 1rem;
    position: relative;
    z-index: 1;
    justify-items: center;
    width: 100%;
    max-width: 100%;
}

.timeline-sessions::-webkit-scrollbar {
    display: none; /* Chrome, Safari, Opera */
}

/* ========== SESSION CARD ========== */
/* Remove row line decoration and add ambient halo */
.session-card {
    width: 100%;
    max-width: 400px;
    position: relative;
    z-index: 0; /* stacking context for halo */
    opacity: 0;
    transform: translateY(30px);
    margin: 15px 0; /* Extra space for glow effects */
}

/* Soft ambient halo behind each card */
.session-card::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 120%;
    height: 140%;
    background: radial-gradient(ellipse at center, rgba(108, 186, 255, 0.12), rgba(0,0,0,0) 60%);
    filter: blur(18px);
    z-index: -1;
    pointer-events: none;
}

/* Ensure the card content sits above the line */
.session-node {
    position: relative;
    z-index: 1;
}

.session-node {
    background: #1c2245;
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 16px;
    padding: 2.5rem 2rem;
    text-decoration: none;
    color: inherit;
    display: block;
    position: relative;
    overflow: hidden;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(10px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.35);
    min-height: 140px;
}

.session-node:hover {
    transform: scale(1.05) translateY(-5px);
    border-color: #6cbaff;
    box-shadow: 
        0 15px 40px rgba(108, 186, 255, 0.3),
        0 0 20px rgba(108, 186, 255, 0.2),
        0 6px 20px rgba(0, 0, 0, 0.35);
}

/* Node connector dot moved to left-center of card */
.session-node::before {
    content: '';
    position: absolute;
    top: 50%;
    left: -24px;
    transform: translateY(-50%);
    width: 12px;
    height: 12px;
    background: radial-gradient(circle at center, #6cbaff, #9b6dff);
    border-radius: 50%;
    box-shadow: 0 0 18px rgba(108, 186, 255, 0.9);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

/* Glow effect overlay */
.session-node::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at center, rgba(108, 186, 255, 0.1), transparent);
    opacity: 0;
    transition: opacity 0.4s ease;
    pointer-events: none;
}


.session-node:hover::before {
    transform: translateY(-50%) scale(1.35);
    box-shadow: 0 0 28px rgba(108, 186, 255, 1);
}

.session-node:hover::after {
    opacity: 1;
}


.session-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: #f5f7ff;
    line-height: 1.6;
    margin: 0;
}

/* ========== FOOTER ========== */
.footer {
    text-align: center;
    padding: 2rem 1rem 3rem;
    color: #a9afc9;
    font-size: 0.9rem;
    border-top: 1px solid rgba(255, 255, 255, 0.12);
    margin-top: 4rem;
}

/* ========== RESPONSIVE ========== */
@media (max-width: 768px) {
    body {
        display: flex;
        justify-content: center;
        align-items: flex-start;
    }
    
    .container {
        padding: 1rem 0.5rem;
        width: 100%;
        max-width: 100%;
        margin: 0;
        display: flex;
        flex-direction: column;
        align-items: center;
    }
    
    .timeline-wrapper {
        padding: 0 0.5rem;
        width: 100%;
        max-width: 100%;
    }
    
    .timeline-sessions {
        grid-template-columns: 1fr;
        gap: 1.5rem;
        padding: 2rem 0.5rem;
        justify-items: center;
        width: 100%;
        max-width: 100%;
    }
    
    .hero {
        padding: 2rem 1rem;
        width: 100%;
        text-align: center;
    }
    
    .language-switcher {
        top: 1rem;
        right: 1rem;
        gap: 0.4rem;
        padding: 0.4rem;
    }
    
    .language-btn {
        padding: 0.45rem 0.7rem;
        font-size: 0.8rem;
        min-width: 38px;
    }
    
    .tab-btn {
        padding: 0.8rem 1.5rem;
        font-size: 1rem;
    }
    
    .session-card {
        width: 100%;
        max-width: 350px;
        margin: 0 auto;
    }
    
    .session-node {
        padding: 2rem 1.5rem;
        min-height: 120px;
    }
    
    .session-title {
        font-size: 1.1rem;
    }
    
    .hall-filters {
        padding: 0 0.5rem;
        width: 100%;
        max-width: 100%;
        justify-content: center;
    }
    
    .day-tabs {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    body {
        display: flex;
        justify-content: center;
        align-items: flex-start;
    }
    
    .container {
        padding: 0.5rem 0.25rem;
        width: 100%;
        max-width: 100%;
        margin: 0;
        display: flex;
        flex-direction: column;
        align-items: center;
    }
    
    .timeline-wrapper {
        padding: 0 0.25rem;
        width: 100%;
        max-width: 100%;
    }
    
    .timeline-sessions {
        grid-template-columns: 1fr;
        gap: 1.2rem;
        padding: 1.5rem 0.25rem;
        justify-items: center;
        width: 100%;
        max-width: 100%;
    }
    
    .session-card {
        width: 100%;
        max-width: 320px;
        margin: 0 auto;
    }
    
    .session-node {
        padding: 1.5rem 1rem;
        min-height: 100px;
    }
    
    .session-title {
        font-size: 1rem;
        line-height: 1.5;
    }
    
    .language-switcher {
        top: 0.5rem;
        right: 0.5rem;
        gap: 0.3rem;
        padding: 0.3rem;
    }
    
    .language-btn {
        padding: 0.4rem 0.6rem;
        font-size: 0.75rem;
        min-width: 34px;
    }
    
    .day-tabs {
        gap: 0.5rem;
        width: 100%;
        justify-content: center;
    }
    
    .tab-btn {
        padding: 0.7rem 1.2rem;
        font-size: 0.9rem;
    }
    
    .hall-filters {
        padding: 0 0.25rem;
        width: 100%;
        max-width: 100%;
        justify-content: center;
    }
}

/* ========== ANIMATIONS ========== */
.fade-in {
    animation: fadeIn 0.6s ease forwards;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Loading state */
.loading {
    text-align: center;
    padding: 3rem;
    color: #a9afc9;
    font-size: 1.1rem;
}

.hall-filters {
    display: flex;
    justify-content: center;
    gap: 0.6rem;
    margin: -1rem 0 2rem;
    flex-wrap: wrap;
    padding: 0 1rem;
    width: 100%;
    max-width: 100%;
}

.hall-btn {
    position: relative;
    padding: 0.6rem 1.1rem 0.6rem 2.1rem; /* leave space for dot */
    font-size: 0.95rem;
    font-weight: 600;
    background: rgba(255, 255, 255, 0.08); /* white translucency */
    border: 1px solid rgba(255, 255, 255, 0.18);
    color: #eef5ff; /* light text */
    border-radius: 999px;
    cursor: pointer;
    transition: transform 0.15s ease, box-shadow 0.25s ease, color 0.25s ease, border-color 0.25s ease, background 0.25s ease;
    backdrop-filter: blur(8px);
}

.hall-btn::before {
    content: '';
    position: absolute;
    left: 10px;
    top: 50%;
    transform: translateY(-50%);
    width: 10px;
    height: 10px;
    border-radius: 50%;
    box-shadow: 0 0 10px currentColor;
}

/* Color dots per hall */
.hall-btn[data-hall="Singularity hall"]::before { background: radial-gradient(circle at 30% 30%, #ffb86c, #ff6b6b); color: #ffb86c; }
.hall-btn[data-hall="Unity hall"]::before { background: radial-gradient(circle at 30% 30%, #6cbaff, #2196f3); color: #6cbaff; }
.hall-btn[data-hall="Vision hall"]::before { background: radial-gradient(circle at 30% 30%, #9b6dff, #673ab7); color: #9b6dff; }
.hall-btn[data-hall="Quantum hall"]::before { background: radial-gradient(circle at 30% 30%, #21d4fd, #00bcd4); color: #21d4fd; }
.hall-btn[data-hall="Generative hall"]::before { background: radial-gradient(circle at 30% 30%, #34eb8f, #00c853); color: #34eb8f; }
.hall-btn[data-hall="all"]::before { background: radial-gradient(circle at 30% 30%, #ffffff, #cfd8dc); color: #ffffff; }

.hall-btn:hover {
    color: #ffffff;
    background: rgba(255, 255, 255, 0.12);
    border-color: rgba(255, 255, 255, 0.28);
    box-shadow: 0 8px 24px rgba(255, 255, 255, 0.12);
    transform: translateY(-1px);
}

.hall-btn.active {
    color: #ffffff;
    background: rgba(255, 255, 255, 0.16);
    border-color: rgba(255, 255, 255, 0.35);
    box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.25), 0 10px 28px rgba(255, 255, 255, 0.18);
}

.hall-btn:focus-visible {
    outline: none;
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.4), 0 10px 28px rgba(255, 255, 255, 0.18);
}

/* ========== SCROLL TO TOP BUTTON ========== */
.scroll-to-top-btn {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 56px;
    height: 56px;
    background: rgba(108, 186, 255, 0.15);
    border: 1px solid rgba(108, 186, 255, 0.3);
    border-radius: 50%;
    color: #6cbaff;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(10px);
    box-shadow: 0 6px 20px rgba(108, 186, 255, 0.2);
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px) scale(0.8);
}

.scroll-to-top-btn:hover {
    background: rgba(108, 186, 255, 0.25);
    border-color: rgba(108, 186, 255, 0.5);
    color: #eaf6ff;
    transform: translateY(-2px) scale(1.05);
    box-shadow: 0 10px 30px rgba(108, 186, 255, 0.4);
}

.scroll-to-top-btn:active {
    transform: translateY(0) scale(1);
}

.scroll-to-top-btn.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0) scale(1);
}

.scroll-to-top-btn svg {
    transition: transform 0.3s ease;
}

.scroll-to-top-btn:hover svg {
    transform: translateY(-2px);
}

@media (max-width: 768px) {
    .scroll-to-top-btn {
        bottom: 1.5rem;
        right: 1.5rem;
        width: 48px;
        height: 48px;
    }
}

@media (max-width: 480px) {
    .scroll-to-top-btn {
        bottom: 1rem;
        right: 1rem;
        width: 44px;
        height: 44px;
    }
}

/* ========== CLEAR FILTERS BUTTON ========== */
.clear-filters-btn {
    padding: 0.6rem 1.4rem;
    font-size: 0.95rem;
    font-weight: 600;
    background: rgba(255, 59, 48, 0.15);
    border: 1px solid rgba(255, 59, 48, 0.4);
    color: #ff8080;
    border-radius: 999px;
    cursor: pointer;
    transition: all 0.25s ease;
    backdrop-filter: blur(8px);
    margin-left: 0.5rem;
    display: none;
}

.clear-filters-btn:hover {
    background: rgba(255, 59, 48, 0.25);
    border-color: rgba(255, 59, 48, 0.6);
    color: #ff9999;
    box-shadow: 0 8px 24px rgba(255, 59, 48, 0.2);
    transform: translateY(-1px);
}

.clear-filters-btn:active {
    transform: translateY(0);
}

.clear-filters-btn:focus-visible {
    outline: none;
    box-shadow: 0 0 0 3px rgba(255, 59, 48, 0.4);
}

@media (max-width: 520px) {
    .hall-btn { font-size: 0.9rem; padding: 0.55rem 1rem 0.55rem 1.9rem; }
    .tab-btn { gap: 0.5rem; padding: 0.9rem 1.6rem; }
    .tab-date { font-size: 0.8rem; padding: 0.15rem 0.5rem; }
    .clear-filters-btn { font-size: 0.85rem; padding: 0.5rem 1.1rem; margin-left: 0; margin-top: 0.5rem; }
}