/* =====================================================
   ORGANIC SYNTHESIS LAB — Clean Professional Theme
   ===================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Space+Grotesk:wght@400;500;600;700;800&display=swap');

*, *::before, *::after { box-sizing: border-box; }

:root {
    --black:       #0a0a0a;
    --dark:        #1c1c1c;
    --gray-800:    #374151;
    --gray-600:    #6b7280;
    --gray-400:    #9ca3af;
    --gray-200:    #e5e7eb;
    --gray-100:    #f3f4f6;
    --gray-50:     #f9fafb;
    --white:       #ffffff;
    --accent:      #166534;
    --accent-mid:  #16a34a;
    --accent-light:#dcfce7;
    --radius-sm:   6px;
    --radius:      10px;
    --radius-lg:   16px;
    --shadow-sm:   0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
    --shadow:      0 4px 16px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.05);
    --shadow-lg:   0 10px 40px rgba(0,0,0,0.12);
}

html { scroll-behavior: smooth; }

body {
    font-family: 'Inter', 'Segoe UI', sans-serif;
    background: var(--gray-50);
    color: var(--gray-800);
    margin: 0;
    line-height: 1.65;
}

/* =====================================================
   NAVBAR  — dark gradient, full redesign
   ===================================================== */
.main-navbar {
    background: linear-gradient(to right, #040c04 0%, #081408 45%, #0b1a0b 100%) !important;
    border-bottom: 1px solid rgba(255,255,255,0.06) !important;
    padding: 0 !important;
    box-shadow: 0 4px 24px rgba(0,0,0,0.45) !important;
    position: sticky;
    top: 0;
    z-index: 100;
}

/* Brand logo wrap */
.brand-logo-wrap {
    width: 40px; height: 40px;
    border-radius: 10px;
    background: rgba(255,255,255,0.07);
    border: 1px solid rgba(255,255,255,0.10);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.lab-logo {
    width: 26px; height: 26px;
    filter: brightness(0) invert(1);
    opacity: 0.85;
}

/* Brand text */
.brand-group {
    display: flex;
    flex-direction: column;
    gap: 1px;
    line-height: 1.2;
}

.brand-text {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1rem;
    font-weight: 700;
    color: var(--white) !important;
    text-decoration: none;
    letter-spacing: -0.2px;
}

.brand-text:hover { color: var(--accent-mid) !important; }

.brand-subtext {
    font-size: 0.67rem;
    color: rgba(255,255,255,0.40);
    font-weight: 400;
    letter-spacing: 0.1px;
    font-family: 'Inter', sans-serif;
}

/* Nav links */
.main-navbar .nav-link {
    color: rgba(255,255,255,0.65) !important;
    font-size: 0.84rem;
    font-weight: 500;
    padding: 0.48rem 1.05rem !important;
    margin: 0 1px;
    border: none;
    transition: color 0.18s, background 0.18s;
    border-radius: 100px !important;
    letter-spacing: 0.1px;
}

.main-navbar .nav-link:hover {
    color: var(--white) !important;
    background: rgba(255,255,255,0.09) !important;
    border-radius: 100px !important;
}

.main-navbar .nav-link.active {
    color: #0a1a0a !important;
    background: rgba(255,255,255,0.94) !important;
    border-radius: 100px !important;
    font-weight: 700;
}

/* Right-side actions */
.navbar-end-btn {
    color: rgba(255,255,255,0.45);
    text-decoration: none;
    font-size: 0.88rem;
    padding: 7px 9px;
    border-radius: 8px;
    border: 1px solid rgba(255,255,255,0.10);
    transition: all 0.18s;
    line-height: 1;
}

.navbar-end-btn:hover {
    color: var(--white);
    background: rgba(255,255,255,0.08);
    border-color: rgba(255,255,255,0.20);
}

.navbar-iitb-logo {
    height: 28px;
    width: auto;
    filter: brightness(0) invert(1);
    opacity: 0.35;
    margin-left: 4px;
}

/* Mobile toggler */
.navbar-toggler {
    border-color: rgba(255,255,255,0.25) !important;
}
.navbar-toggler-icon {
    filter: invert(1);
}

@media (min-width: 992px) {
    .main-navbar .container-fluid { position: relative; }
    .main-navbar .navbar-collapse {
        position: absolute !important;
        left: 50%;
        top: 50%;
        transform: translate(-50%, -50%);
        width: auto !important;
        flex-basis: auto !important;
        display: flex !important;
        background: transparent;
    }
    .main-navbar .navbar-collapse .navbar-nav {
        pointer-events: auto;
        flex-direction: row !important;
    }
}

@media (max-width: 991px) {
    .brand-subtext { display: none; }
    .main-navbar .navbar-collapse {
        background: #060e06;
        border-top: 1px solid rgba(255,255,255,0.06);
        padding: 12px 8px 16px;
        border-radius: 0 0 12px 12px;
    }
    .main-navbar .nav-link {
        padding: 0.55rem 1rem !important;
        border-radius: 8px !important;
    }
}

/* =====================================================
   HOME — HERO CAROUSEL
   ===================================================== */
.hero-section {
    background: var(--black);
    padding: 0;
}

.carousel-wrapper {
    max-width: 100%;
    margin: 0;
    padding: 0;
}

#mainCarousel { border-radius: 0; overflow: hidden; box-shadow: none; }
.carousel-inner { border-radius: 0; }

/* Split-panel slides: gradient text left · real image right */
.carousel-slide-bg {
    height: 520px;
    width: 100%;
    display: flex;
    align-items: stretch;
    position: relative;
    overflow: hidden;
}

/* Left text panel — transparent so gradient bg shows through */
.slide-split-text {
    flex: 0 0 44%;
    display: flex;
    align-items: center;
    position: relative;
    z-index: 2;
}

/* Right image panel */
.slide-split-image {
    flex: 1;
    position: relative;
    overflow: hidden;
}

.slide-photo {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center top;
    display: block;
}

/* Gradient fade from the slide colour into the photo */
.slide-split-image::before {
    content: '';
    position: absolute;
    left: 0; top: 0; bottom: 0;
    width: 140px;
    z-index: 1;
    pointer-events: none;
}
.slide-bg-1 .slide-split-image::before { background: linear-gradient(to right, #0f2e14, transparent); }
.slide-bg-2 .slide-split-image::before { background: linear-gradient(to right, #0a3d3d, transparent); }
.slide-bg-3 .slide-split-image::before { background: linear-gradient(to right, #0e0e4a, transparent); }
.slide-bg-4 .slide-split-image::before { background: linear-gradient(to right, #320e0e, transparent); }
.slide-bg-5 .slide-split-image::before { background: linear-gradient(to right, #221e04, transparent); }

/* Slide backgrounds — rich CSS gradients, no images */
.slide-bg-1 {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(22,163,74,0.13) 0%, transparent 55%),
        linear-gradient(155deg, #020d02 0%, #0b2210 55%, #112c15 100%);
}
.slide-bg-2 {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(13,148,136,0.12) 0%, transparent 55%),
        linear-gradient(155deg, #01100f 0%, #073238 55%, #0a3d3d 100%);
}
.slide-bg-3 {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(99,102,241,0.10) 0%, transparent 55%),
        linear-gradient(155deg, #020208 0%, #09093a 55%, #0e0e4a 100%);
}
.slide-bg-4 {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(220,38,38,0.09) 0%, transparent 55%),
        linear-gradient(155deg, #100101 0%, #280a0a 55%, #320e0e 100%);
}
.slide-bg-5 {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(234,179,8,0.09) 0%, transparent 55%),
        linear-gradient(155deg, #0a0a02 0%, #1a1a06 55%, #221e04 100%);
}

/* Large decorative icon — right side of each slide */
.slide-deco {
    position: absolute;
    right: 8%;
    top: 50%;
    transform: translateY(-50%);
    font-size: 18rem;
    line-height: 1;
    color: #fff;
    opacity: 0.05;
    pointer-events: none;
    user-select: none;
}


/* Large decorative number */
.slide-number {
    position: absolute;
    right: -20px;
    bottom: -80px;
    font-family: 'Space Grotesk', sans-serif;
    font-size: 36rem;
    font-weight: 900;
    line-height: 1;
    color: rgba(255,255,255,0.04);
    pointer-events: none;
    user-select: none;
    letter-spacing: -2rem;
}

/* Slide vertical accent bar */
.slide-content-wrap {
    padding: 0 52px;
    position: relative;
    z-index: 2;
    max-width: 800px;
}

.slide-content-wrap::before {
    content: '';
    display: block;
    width: 3px;
    height: 52px;
    background: var(--accent-mid);
    margin-bottom: 24px;
    border-radius: 2px;
}

.slide-caption-tag {
    display: inline-block;
    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--accent-mid);
    margin-bottom: 16px;
    display: block;
}

.slide-caption h5 {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 3rem;
    font-weight: 800;
    color: var(--white);
    line-height: 1.1;
    margin-bottom: 18px;
    letter-spacing: -1px;
}

.slide-caption p {
    font-size: 1rem;
    color: rgba(255,255,255,0.55);
    line-height: 1.75;
    margin: 0;
    max-width: 500px;
}

/* Indicators — bottom center */
.carousel-indicators {
    bottom: 28px;
    top: auto;
    z-index: 10;
    margin: 0;
    gap: 6px;
    justify-content: center;
}

.carousel-indicators [data-bs-target] {
    width: 28px; height: 3px;
    border-radius: 2px;
    background-color: rgba(255,255,255,0.3);
    border: none;
    margin: 0;
    opacity: 1;
    transition: all 0.25s;
}

.carousel-indicators .active {
    background-color: var(--accent-mid);
    width: 44px;
}

/* Pause/Play */
.pause-btn {
    position: absolute;
    top: 20px; right: 20px;
    z-index: 20;
    width: 36px; height: 36px;
    border-radius: var(--radius-sm);
    background: rgba(255,255,255,0.1);
    border: 1px solid rgba(255,255,255,0.15);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: rgba(255,255,255,0.7);
    font-size: 10px;
    transition: all 0.2s;
    backdrop-filter: blur(4px);
}

.pause-btn:hover { background: rgba(255,255,255,0.2); color: #fff; }

/* Prev/Next arrows */
.carousel-control-prev,
.carousel-control-next {
    width: 48px; height: 48px;
    border-radius: 50%;
    background: rgba(255,255,255,0.1);
    border: 1px solid rgba(255,255,255,0.15);
    top: 50%; bottom: auto;
    transform: translateY(-50%);
    opacity: 1;
    transition: all 0.2s;
    backdrop-filter: blur(4px);
}

.carousel-control-prev { left: 24px; }
.carousel-control-next { right: 24px; }

.carousel-control-prev:hover,
.carousel-control-next:hover {
    background: var(--accent);
    border-color: var(--accent);
    opacity: 1;
}

.carousel-control-prev-icon,
.carousel-control-next-icon {
    width: 16px; height: 16px;
}

/* Thumbnail strip — removed, using indicators instead */
.thumbnail-strip { display: none; }

/* =====================================================
   HOME — WELCOME SECTION
   ===================================================== */
.welcome-section {
    background: var(--white);
    padding: 80px 0 96px;
    border-bottom: 1px solid var(--gray-200);
}

.welcome-inner {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 32px;
}

.section-tag {
    font-size: 0.72rem;
    font-weight: 700;
    letter-spacing: 2.5px;
    text-transform: uppercase;
    color: var(--accent-mid);
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.section-tag::before {
    content: '';
    width: 20px; height: 2px;
    background: var(--accent-mid);
    border-radius: 1px;
    flex-shrink: 0;
}

.welcome-eyebrow { /* alias */ font-size: 0.72rem; font-weight: 700; letter-spacing: 2.5px; text-transform: uppercase; color: var(--accent-mid); margin-bottom: 12px; }

.welcome-title {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 2.4rem;
    font-weight: 700;
    color: var(--black);
    margin-bottom: 16px;
    line-height: 1.2;
    letter-spacing: -0.5px;
    max-width: 680px;
}

.welcome-desc {
    font-size: 1rem;
    color: var(--gray-600);
    margin-bottom: 56px;
    max-width: 560px;
    line-height: 1.75;
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 16px;
}

.research-tile {
    background: var(--gray-50);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    padding: 24px 20px;
    display: flex;
    align-items: center;
    gap: 16px;
    transition: all 0.2s;
    cursor: default;
}

.research-tile:hover {
    background: var(--white);
    border-color: var(--accent-mid);
    box-shadow: var(--shadow-sm);
    transform: translateY(-2px);
}

.research-tile-icon {
    width: 44px; height: 44px;
    border-radius: var(--radius-sm);
    background: var(--accent-light);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    font-size: 1.05rem;
    color: var(--accent);
}

.research-tile-label {
    font-size: 0.88rem;
    font-weight: 600;
    color: var(--gray-800);
    margin: 0;
    line-height: 1.35;
}

/* =====================================================
   SHARED PAGE STYLES
   ===================================================== */
.page-bg {
    background: var(--gray-50);
    padding-bottom: 80px;
    min-height: 80vh;
}

/* Page banner */
.page-banner-wrap {
    width: 100%;
    height: 270px;
    position: relative;
    display: flex;
    align-items: flex-end;
    overflow: hidden;
}

/* Banner classes — CSS-only themed gradients, no images */

/* Academics — deep navy, education theme */
.page-banner-wrap.academics-banner {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(59,130,246,0.12) 0%, transparent 55%),
        linear-gradient(155deg, #010510 0%, #060f2a 55%, #0b163a 100%);
}

/* Research — dark teal, science theme */
.page-banner-wrap.research-banner {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(13,148,136,0.14) 0%, transparent 55%),
        linear-gradient(155deg, #01100f 0%, #073238 55%, #0a3d3d 100%);
}

/* Group — forest green, people theme */
.page-banner-wrap.group-banner {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(22,163,74,0.14) 0%, transparent 55%),
        linear-gradient(155deg, #020d02 0%, #0b2210 55%, #112c15 100%);
}

/* Gallery — deep violet, visual/art theme */
.page-banner-wrap.gallery-banner {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(139,92,246,0.12) 0%, transparent 55%),
        linear-gradient(155deg, #080212 0%, #160838 55%, #1c0a45 100%);
}

/* Publications — dark amber, scholarly theme */
.page-banner-wrap.pub-banner {
    background:
        radial-gradient(ellipse at 78% 50%, rgba(234,179,8,0.10) 0%, transparent 55%),
        linear-gradient(155deg, #0a0802 0%, #1e1804 55%, #261e04 100%);
}

/* Banner photo panel — occupies the right half */
.banner-photo-side {
    position: absolute;
    right: 0;
    top: 0;
    height: 100%;
    width: 52%;
    overflow: hidden;
    z-index: 1;
}

.banner-photo-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center;
    display: block;
    opacity: 0.85;
}

/* Fade from the banner gradient into the photo */
.banner-photo-side::before {
    content: '';
    position: absolute;
    left: 0; top: 0; bottom: 0;
    width: 160px;
    z-index: 2;
    pointer-events: none;
}
.academics-banner .banner-photo-side::before { background: linear-gradient(to right, #0b163a, transparent); }
.research-banner  .banner-photo-side::before { background: linear-gradient(to right, #0a3d3d, transparent); }
.group-banner     .banner-photo-side::before { background: linear-gradient(to right, #112c15, transparent); }
.gallery-banner   .banner-photo-side::before { background: linear-gradient(to right, #1c0a45, transparent); }
.pub-banner       .banner-photo-side::before { background: linear-gradient(to right, #261e04, transparent); }

.banner-inner {
    width: 100%;
    padding: 0 0 28px 40px;
    position: relative;
    z-index: 3;
    max-width: 1320px;
    margin: 0 auto;
}

/* Old banner-icon hidden — replaced by .banner-img-panel */
.banner-icon { display: none; }

/* ── Banner visual panel (themed icon + concentric rings) ── */
.banner-img-panel {
    position: absolute;
    right: 7%;
    top: 50%;
    transform: translateY(-50%);
    width: 230px;
    height: 230px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 12px;
    pointer-events: none;
}

.bip-ring {
    position: absolute;
    border-radius: 50%;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
}

.r1 { width: 96px;  height: 96px;  border: 1px solid rgba(255,255,255,0.14); }
.r2 { width: 168px; height: 168px; border: 1px solid rgba(255,255,255,0.08); }
.r3 { width: 240px; height: 240px; border: 1px solid rgba(255,255,255,0.04); }

.bip-icon {
    font-size: 3.6rem;
    position: relative;
    z-index: 2;
    color: rgba(255,255,255,0.18);
}

.bip-caption {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 0.6rem;
    font-weight: 700;
    letter-spacing: 3px;
    text-transform: uppercase;
    color: rgba(255,255,255,0.14);
    position: relative;
    z-index: 2;
}

/* Per-page icon accent tints */
.academics-banner .bip-icon { color: rgba(99,142,255,0.35); }
.research-banner  .bip-icon { color: rgba(45,212,191,0.35); }
.group-banner     .bip-icon { color: rgba(74,222,128,0.35); }
.gallery-banner   .bip-icon { color: rgba(192,132,252,0.35); }
.pub-banner       .bip-icon { color: rgba(251,191,36,0.35);  }

/* ── Slider decorative panel (rings + icon) ── */
.slide-deco {
    position: absolute;
    right: 8%;
    top: 50%;
    transform: translateY(-50%);
    width: 300px;
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    pointer-events: none;
    user-select: none;
    font-size: 0;
}

.slide-deco i {
    font-size: 7rem;
    color: rgba(255,255,255,0.12);
    position: relative;
    z-index: 2;
}

.sd-ring {
    position: absolute;
    border-radius: 50%;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
}

.sd-r1 { width: 130px; height: 130px; border: 1px solid rgba(255,255,255,0.12); }
.sd-r2 { width: 220px; height: 220px; border: 1px solid rgba(255,255,255,0.07); }
.sd-r3 { width: 310px; height: 310px; border: 1px solid rgba(255,255,255,0.04); }

.banner-label {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 3px;
    text-transform: uppercase;
    color: var(--accent-mid);
    display: block;
    margin-bottom: 6px;
}

.banner-title {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 2rem;
    font-weight: 700;
    color: var(--white);
    margin: 0;
    letter-spacing: -0.3px;
}

.page-title {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 2rem;
    font-weight: 700;
    color: var(--black);
    padding: 40px 0 24px;
    letter-spacing: -0.3px;
    margin: 0;
}

.content-card {
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-lg);
    padding: 44px 52px 52px;
    max-width: 960px;
    margin: 0 auto;
    box-shadow: var(--shadow-sm);
}

.container > .page-title {
    max-width: 960px;
    margin-left: auto;
    margin-right: auto;
}

/* =====================================================
   ACADEMICS
   ===================================================== */
.program-label {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--accent);
    margin-bottom: 16px;
    margin-top: 8px;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.program-label::before {
    content: '';
    width: 14px; height: 2px;
    background: var(--accent-mid);
    flex-shrink: 0;
}

.col-heading {
    font-weight: 700;
    font-size: 0.82rem;
    color: var(--gray-800);
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.course-list {
    list-style: none;
    padding: 0; margin: 0;
    font-size: 0.87rem;
    color: var(--gray-600);
    line-height: 2.1;
}

.course-list li { padding-left: 16px; position: relative; }

.course-list li::before {
    content: '·';
    position: absolute;
    left: 4px;
    color: var(--accent-mid);
    font-weight: 700;
}

hr.section-divider {
    border: 0;
    border-top: 1px solid var(--gray-100);
    margin: 32px 0;
}

/* =====================================================
   RESEARCH
   ===================================================== */
.research-intro-text {
    font-size: 0.95rem;
    color: var(--gray-600);
    line-height: 1.9;
    margin-bottom: 36px;
    padding: 20px 24px;
    background: var(--gray-50);
    border-left: 3px solid var(--accent-mid);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.research-section-title {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1rem;
    font-weight: 700;
    color: var(--black);
    margin-bottom: 14px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.research-section-title::before {
    content: '';
    width: 4px; height: 18px;
    background: var(--accent-mid);
    border-radius: 2px;
    flex-shrink: 0;
}

.research-body-text {
    font-size: 0.9rem;
    color: var(--gray-600);
    line-height: 1.9;
    margin-bottom: 24px;
}

/* Sample research figure — clean placeholder */
.sample-figure {
    max-width: 560px;
    margin: 28px 0 36px;
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.fig-placeholder {
    height: 200px;
    background: var(--gray-50);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 14px;
    color: var(--gray-400);
    position: relative;
}

.fig-placeholder::before {
    content: '';
    position: absolute;
    inset: 16px;
    border: 1px dashed var(--gray-200);
    border-radius: var(--radius-sm);
    pointer-events: none;
}

.fig-placeholder i {
    font-size: 2.4rem;
    color: var(--gray-300);
}

.fig-placeholder span {
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.5px;
    text-transform: uppercase;
    color: var(--gray-400);
}

.fig-caption {
    font-size: 0.78rem;
    font-weight: 500;
    color: var(--gray-500, #6b7280);
    margin: 0;
    padding: 10px 16px;
    background: var(--white);
    border-top: 1px solid var(--gray-200);
}

/* =====================================================
   GROUP
   ===================================================== */
.group-tab-bar {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 32px;
    padding: 4px;
    background: var(--gray-100);
    border-radius: var(--radius);
    width: fit-content;
}

.tab-label-active { display: none; }

.tab-pill {
    background: transparent;
    color: var(--gray-600);
    border: none;
    padding: 8px 20px;
    border-radius: var(--radius-sm);
    font-size: 0.82rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
    letter-spacing: 0.1px;
}

.tab-pill:hover { background: var(--white); color: var(--gray-800); }

.tab-pill.active-tab {
    background: var(--white);
    color: var(--black);
    box-shadow: var(--shadow-sm);
}

.tab-pane-content { display: none; }
.tab-pane-content.visible { display: block; }

.student-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 24px 16px;
    margin-top: 8px;
}

.student-card {
    text-align: center;
    padding: 20px 10px 18px;
    border-radius: var(--radius);
    transition: all 0.2s;
    cursor: default;
}

.student-card:hover {
    background: var(--gray-50);
    box-shadow: var(--shadow-sm);
}

.student-photo {
    width: 80px; height: 80px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--gray-200);
    display: block;
    margin: 0 auto 12px;
    background: var(--gray-100);
}

/* Avatar circle for initials */
.avatar-circle {
    width: 80px; height: 80px;
    border-radius: 50%;
    background: var(--black);
    border: 2px solid var(--gray-200);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 12px;
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1.1rem;
    font-weight: 800;
    color: var(--white);
    letter-spacing: 0.5px;
    flex-shrink: 0;
}

.avatar-circle.av-light {
    background: var(--gray-100);
    color: var(--black);
    border-color: var(--gray-300);
}

.avatar-circle.av-mid {
    background: var(--gray-800);
    color: var(--white);
}

.student-card:hover .avatar-circle {
    border-color: var(--accent-mid);
}

.student-name {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--gray-800);
    margin: 0 0 4px;
    line-height: 1.35;
}

.student-fellowship {
    font-size: 0.67rem;
    color: var(--accent);
    margin: 0;
    font-weight: 700;
    letter-spacing: 0.3px;
    background: var(--accent-light);
    display: inline-block;
    padding: 1px 7px;
    border-radius: 4px;
}

/* Professor */
.prof-name {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--black);
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--gray-200);
}

.prof-profile-row {
    display: flex;
    gap: 36px;
    align-items: flex-start;
    margin-bottom: 28px;
}

.prof-photo-wrap { flex-shrink: 0; }

.prof-photo {
    width: 130px; height: 130px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--gray-200);
    display: block;
}

.prof-photo-placeholder {
    width: 130px; height: 130px;
    border-radius: 50%;
    background: var(--black);
    border: 3px solid var(--gray-200);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1.4rem;
    font-weight: 800;
}

.prof-info { line-height: 1.85; font-size: 0.9rem; color: var(--gray-600); }
.prof-info strong { color: var(--gray-800); font-weight: 600; }

.prof-bio {
    font-size: 0.88rem;
    color: var(--gray-600);
    line-height: 1.9;
    margin-bottom: 18px;
}

.cv-link-line {
    font-size: 0.88rem;
    color: var(--gray-600);
    margin-bottom: 28px;
}

.cv-link-line a { color: var(--accent); font-weight: 600; text-decoration: underline; }

.contact-section h6 {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 700;
    font-size: 0.82rem;
    color: var(--black);
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.contact-section p {
    font-size: 0.87rem;
    color: var(--gray-600);
    line-height: 2;
    margin: 0;
}

.contact-section a { color: var(--accent); font-weight: 500; text-decoration: none; }
.contact-section a:hover { text-decoration: underline; }

/* =====================================================
   FOOTER
   ===================================================== */
.site-footer {
    background: var(--black);
    color: var(--gray-400);
    padding: 60px 0 0;
}

.footer-contact { font-size: 0.87rem; line-height: 1.75; }
.footer-contact p { margin-bottom: 16px; color: var(--gray-400); }
.footer-contact i { margin-right: 6px; color: var(--accent-mid); width: 14px; }
.footer-contact a { color: var(--gray-400); text-decoration: underline; transition: color 0.2s; }
.footer-contact a:hover { color: var(--white); }

.footer-section-title {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--white);
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 1px solid rgba(255,255,255,0.08);
}

.footer-link-list {
    list-style: none;
    padding: 0; margin: 0;
    font-size: 0.87rem;
    line-height: 2.3;
}

.footer-link-list a {
    color: var(--gray-400);
    text-decoration: none;
    transition: color 0.2s;
}

.footer-link-list a:hover { color: var(--white); }

.iitb-logo {
    max-width: 100px;
    display: block;
    margin: 0 auto;
    filter: brightness(0) invert(0.45);
}

.footer-bottom-bar {
    border-top: 1px solid rgba(255,255,255,0.06);
    margin-top: 48px;
    padding: 18px 0;
    text-align: right;
    font-size: 0.78rem;
    color: rgba(255,255,255,0.2);
}

/* =====================================================
   PUBLICATIONS
   ===================================================== */
.pub-nav-link {
    color: var(--accent);
    text-decoration: none;
    font-size: 0.88rem;
    font-weight: 600;
}
.pub-nav-link:hover { text-decoration: underline; }

.year-index-line {
    font-size: 0.87rem;
    margin-bottom: 6px;
    line-height: 2.2;
}

.year-link {
    color: var(--gray-600);
    text-decoration: none;
    font-size: 0.87rem;
    font-weight: 500;
    transition: color 0.15s;
}
.year-link:hover { color: var(--accent); }

.year-sep { color: var(--gray-200); margin: 0 2px; }

.year-heading {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1.65rem;
    font-weight: 800;
    color: var(--black);
    margin: 48px 0 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--gray-100);
    display: flex;
    align-items: center;
    gap: 12px;
}

.year-heading::before {
    content: '';
    width: 4px; height: 28px;
    background: var(--accent-mid);
    border-radius: 2px;
    flex-shrink: 0;
}

.pub-entry {
    margin-bottom: 32px;
    padding-bottom: 32px;
    border-bottom: 1px solid var(--gray-100);
}

.pub-entry:last-child { border-bottom: none; }

.pub-text {
    font-size: 0.88rem;
    line-height: 1.8;
    color: var(--gray-600);
    margin-bottom: 8px;
}

.pub-title { font-weight: 700; color: var(--gray-800); }

.pub-highlights {
    list-style: none;
    padding-left: 0;
    font-size: 0.84rem;
    color: var(--gray-600);
    margin-bottom: 10px;
    line-height: 1.9;
}

.pub-highlights li::before {
    content: '· ';
    color: var(--accent-mid);
    font-weight: 700;
}

.pub-img-wrap { margin: 12px 0 18px; }

/* Sample publication image */
.sample-pub-img {
    width: 530px;
    max-width: 100%;
    height: 140px;
    background: var(--gray-50);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    color: var(--gray-400);
    font-size: 0.78rem;
    font-weight: 600;
    letter-spacing: 0.5px;
    text-transform: uppercase;
}

.sample-pub-img i {
    font-size: 1.6rem;
    color: var(--gray-300);
}

.doi-link {
    color: var(--accent);
    text-decoration: none;
    font-weight: 500;
}
.doi-link:hover { text-decoration: underline; }

/* =====================================================
   GALLERY
   ===================================================== */
.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
    gap: 14px;
    margin-top: 16px;
}

.gallery-item {
    overflow: hidden;
    border-radius: var(--radius);
    border: 1px solid var(--gray-200);
    background: var(--white);
    transition: all 0.25s;
    box-shadow: var(--shadow-sm);
}

.gallery-item:hover {
    box-shadow: var(--shadow);
    transform: translateY(-3px);
}

/* B&W geometric sample photos */
.gallery-sample {
    width: 100%;
    height: 220px;
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-end;
    padding: 14px;
    position: relative;
    transition: opacity 0.25s;
}

.gallery-sample::after {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(to top, rgba(0,0,0,0.5) 0%, transparent 60%);
    pointer-events: none;
}

.gallery-sample-label {
    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    color: var(--white);
    position: relative;
    z-index: 2;
}

/* 9 unique geometric patterns */
.gs-1 { background: #0a0a0a; }
.gs-2 {
    background-color: #f0f0f0;
    background-image: repeating-linear-gradient(
        0deg, transparent, transparent 19px, #bbb 19px, #bbb 20px
    ),repeating-linear-gradient(
        90deg, transparent, transparent 19px, #bbb 19px, #bbb 20px
    );
}
.gs-3 {
    background-color: #fff;
    background-image: radial-gradient(circle, #ccc 1.5px, transparent 1.5px);
    background-size: 22px 22px;
}
.gs-4 {
    background: #1a1a1a;
    background-image: radial-gradient(circle, rgba(255,255,255,0.2) 1.5px, transparent 1.5px);
    background-size: 18px 18px;
}
.gs-5 {
    background-color: #f5f5f5;
    background-image: repeating-linear-gradient(
        45deg, #bbb 0, #bbb 1px, #f5f5f5 0, #f5f5f5 16px
    );
}
.gs-6 {
    background-color: #fff;
    background-image: repeating-linear-gradient(
        -45deg, #ccc 0, #ccc 1px, #fff 0, #fff 14px
    );
}
.gs-7 { background: #111; }
.gs-8 {
    background-color: #f0f0f0;
    background-image: repeating-linear-gradient(
        90deg, #aaa 0, #aaa 1px, transparent 0, transparent 12px
    );
}
.gs-9 {
    background-color: #fafafa;
    background-image:
        repeating-linear-gradient(45deg, #ccc 0, #ccc 1px, transparent 0, transparent 20px),
        repeating-linear-gradient(-45deg, #ccc 0, #ccc 1px, transparent 0, transparent 20px);
}

/* =====================================================
   RESPONSIVE
   ===================================================== */
@media (max-width: 992px) {
    .content-card { padding: 32px 28px; }
    .research-grid { grid-template-columns: repeat(2, 1fr); }
    .carousel-slide-bg { height: 400px; }
    .slide-split-text { flex: 0 0 50%; }
    .slide-content-wrap { padding: 0 36px; }
    .slide-caption h5 { font-size: 2.2rem; }
    .banner-photo-side { width: 44%; }
}

@media (max-width: 768px) {
    .carousel-slide-bg { height: auto; flex-direction: column-reverse; }
    .slide-split-text { flex: none; padding: 36px 0; }
    .slide-split-image { height: 220px; flex: none; width: 100%; }
    .slide-content-wrap { padding: 0 28px; }
    .slide-caption h5 { font-size: 1.7rem; }
    .slide-caption p { display: none; }
    .slide-number { font-size: 14rem; }
    .banner-photo-side { display: none; }
    .welcome-title { font-size: 1.8rem; }
    .research-grid { grid-template-columns: 1fr 1fr; }
    .prof-profile-row { flex-direction: column; align-items: flex-start; }
    .footer-bottom-bar { text-align: center; }
    .content-card { padding: 24px 20px; }
    .page-banner-wrap { height: 200px; }
    .banner-inner { padding-left: 20px; }
    .banner-icon { display: none; }
    .page-title { font-size: 1.7rem; }
    .group-tab-bar { width: 100%; }
    .tab-pill { flex: 1; text-align: center; }
}

@media (max-width: 500px) {
    .research-grid { grid-template-columns: 1fr 1fr; }
    .gallery-grid { grid-template-columns: 1fr 1fr; }
}

/* =====================================================
   INNER PAGE — SIDEBAR + SECTION PANELS LAYOUT
   ===================================================== */

/* Reset old single-card */
.content-card {
    background: transparent !important;
    border: none !important;
    box-shadow: none !important;
    padding: 0 !important;
    max-width: none !important;
    border-radius: 0 !important;
    margin: 0 !important;
}
.page-title { display: none; }
.page-bg { padding-bottom: 0 !important; min-height: unset !important; }

/* 2-column wrapper */
.inner-layout {
    display: flex;
    gap: 24px;
    align-items: flex-start;
    padding: 36px 0 80px;
}

/* Sticky left sidebar */
.inner-sidebar {
    width: 214px;
    flex-shrink: 0;
    position: sticky;
    top: 64px;
}

.isb-widget {
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    overflow: hidden;
    margin-bottom: 10px;
    box-shadow: var(--shadow-sm);
}

.isb-head {
    background: var(--black);
    padding: 12px 16px;
    display: flex;
    align-items: center;
    gap: 9px;
}

.isb-head-icon {
    color: var(--accent-mid);
    font-size: 0.8rem;
    flex-shrink: 0;
    width: 14px;
    text-align: center;
}

.isb-head-label {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 0.65rem;
    font-weight: 700;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--white);
}

.isb-body {
    padding: 5px 0;
}

.isb-link {
    display: flex;
    align-items: center;
    gap: 9px;
    padding: 8px 16px;
    font-size: 0.79rem;
    font-weight: 500;
    color: var(--gray-600);
    text-decoration: none;
    border-left: 3px solid transparent;
    transition: all 0.14s;
    line-height: 1.3;
}

.isb-link:hover {
    color: var(--accent);
    border-left-color: var(--accent-mid);
    background: var(--gray-50);
    text-decoration: none;
}

.isb-link i {
    font-size: 0.6rem;
    color: var(--gray-400);
    flex-shrink: 0;
    width: 10px;
    transition: color 0.14s;
}

.isb-link:hover i { color: var(--accent-mid); }

.isb-rule {
    height: 1px;
    background: var(--gray-100);
    margin: 4px 16px;
}

/* Main content column */
.inner-main { flex: 1; min-width: 0; }

/* Section panels */
.sp {
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-radius: var(--radius);
    padding: 28px 32px 32px;
    margin-bottom: 12px;
    box-shadow: var(--shadow-sm);
}

.sp-intro { border-top: 3px solid var(--accent-mid); }

.sp-head {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
    padding-bottom: 14px;
    border-bottom: 1px solid var(--gray-100);
}

.sp-icon {
    width: 34px; height: 34px;
    border-radius: var(--radius-sm);
    background: var(--accent-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    color: var(--accent);
    flex-shrink: 0;
}

.sp-title {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 1rem;
    font-weight: 700;
    color: var(--black);
    margin: 0;
    letter-spacing: -0.1px;
}

.sp-cols {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px 40px;
}

.sp-col-label {
    font-weight: 700;
    font-size: 0.74rem;
    color: var(--gray-800);
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    padding-bottom: 6px;
    border-bottom: 1px solid var(--gray-100);
}

/* Publications main panel (tall single block) */
.sp-pubs {
    background: var(--white);
    border: 1px solid var(--gray-200);
    border-top: 3px solid var(--accent-mid);
    border-radius: var(--radius);
    padding: 28px 36px 44px;
    box-shadow: var(--shadow-sm);
}

/* Scrollable sidebar for year list */
.isb-body-scroll {
    max-height: 320px;
    overflow-y: auto;
    padding: 5px 0;
    scrollbar-width: thin;
    scrollbar-color: var(--gray-300) transparent;
}

/* Responsive: collapse sidebar to horizontal pill row */
@media (max-width: 992px) {
    .inner-layout { flex-direction: column; gap: 12px; padding: 20px 0 60px; }
    .inner-sidebar { width: 100%; position: static; }
    .isb-body, .isb-body-scroll { display: flex; flex-wrap: wrap; padding: 8px; gap: 4px; max-height: none; overflow: visible; }
    .isb-link {
        border: 1px solid var(--gray-200);
        border-left: 1px solid var(--gray-200) !important;
        border-radius: 20px;
        padding: 5px 12px;
        font-size: 0.74rem;
    }
    .isb-link:hover {
        border-color: var(--accent-mid) !important;
        background: var(--accent-light);
    }
    .isb-rule { display: none; }
    .sp { padding: 20px 18px; }
    .sp-cols { grid-template-columns: 1fr; gap: 14px; }
    .sp-pubs { padding: 20px 18px; }
}

@media (max-width: 768px) {
    .inner-layout { padding: 16px 0 48px; }
}