/* ════════════════════════════════════════════════
   global.css — EE IITH Department Website
   Single source of truth for all shared styles.
   Load this first on every page, before nav.css
   and any page-specific stylesheet.
   ════════════════════════════════════════════════ */

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

html, body {
    overflow-x: hidden;
}

body {
    font-family: system-ui, -apple-system, "Segoe UI", Roboto,
                 "Helvetica Neue", Arial, sans-serif;
    background: #ffffff;
    color: #222;
    line-height: 1.6;
}

img { display: block; max-width: 100%; }
a   { color: inherit; }
button { font-family: inherit; cursor: pointer; }

/* ── DESIGN TOKENS ────────────────────────────── */
:root {
    /* Brand */
    --navy:     #0F1B4C;
    --accent:   #C4671A;

    /* Grays */
    --gray-1:   #f4f4f4;
    --gray-2:   #e0e0e0;
    --gray-3:   #8d8d8d;
    --gray-4:   #525252;

    /* Research streams */
    --cspl:     #F6921D;
    --vlsi:     #00AFBC;
    --peps:     #a37cf0;
    --syscon:   #72BE44;

    /* Nav */
    --nav-height: 56px;

    /* Layout */
    --max-w:    1280px;
    --sidebar-w: 200px;
    --page-pad: 2rem;
    --gap:      2.5rem;
}

/* ── PLAIN HERO (all non-homepage pages) ──────── */
.page-hero {
    background: var(--navy);
    border-bottom: 4px solid var(--accent);
    padding: 3.5rem var(--page-pad);
}

.page-hero-inner {
    max-width: var(--max-w);
    margin: 0 auto;
    display: grid;
    gap: 0.4rem;
}

.page-hero-eyebrow {
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--accent);
}

.page-hero-title {
    font-size: clamp(1.8rem, 4vw, 2.8rem);
    font-weight: 700;
    color: #ffffff;
    line-height: 1.2;
}

.page-hero-sub {
    font-size: 1rem;
    color: rgba(255,255,255,0.55);
    font-weight: 300;
}

/* ── PAGE INTRO — aligned with main content column ─ */
/* Uses same grid as .page-body so content lines up with the main column */
.page-intro {
    display: grid;
    grid-template-columns: var(--sidebar-w) 1fr;
    gap: var(--gap);
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 2.5rem var(--page-pad) 0;
}

.page-intro-content {
    min-width: 0;
}

@media (max-width: 900px) {
    .page-intro {
        grid-template-columns: 1fr;
        padding: 2rem 1.5rem 0;
    }
    .page-intro > :first-child { display: none; } /* hide spacer on mobile */
}

/* ── PAGE BODY — sidebar + main layout ───────── */
.page-body {
    display: grid;
    grid-template-columns: var(--sidebar-w) 1fr;
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 1.75rem var(--page-pad) 3rem;
    gap: var(--gap);
    align-items: start;
    width: 100%;
}

/* ── SIDEBAR ──────────────────────────────────── */
.page-sidebar {
    min-width: 0;
    position: sticky;
    top: calc(var(--nav-height) + 1rem);
    padding-top: 1rem;
}

.sidebar-section {
    border-left: 3px solid var(--navy);
}

.sidebar-heading {
    display: block;
    font-size: 0.82rem;
    font-weight: 600;
    color: #333;
    text-decoration: none;
    padding: 0.55rem 0.75rem;
    border-bottom: 1px solid var(--gray-2);
    transition: color 0.15s;
    word-break: break-word;
}

.sidebar-heading:hover { color: var(--accent); text-decoration: none; }

.sidebar-sub {
    display: block;
    font-size: 0.78rem;
    color: var(--gray-3);
    text-decoration: none;
    padding: 0.35rem 0.75rem 0.35rem 1.4rem;
    border-bottom: 1px solid var(--gray-2);
    transition: color 0.15s;
    word-break: break-word;
}

.sidebar-sub:hover { color: var(--accent); text-decoration: none; }

/* ── MAIN CONTENT ─────────────────────────────── */
.page-main {
    min-width: 0;
    display: grid;
    gap: 0;
    grid-template-columns: minmax(0, 1fr);
}

.page-section {
    display: grid;
    gap: 0.85rem;
    padding: 1.25rem 0;
}

.page-divider {
    height: 1px;
    background: var(--gray-2);
}

/* ── SECTION LABELS ───────────────────────────── */
.section-eyebrow {
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--accent);
}

.section-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--navy);
    line-height: 1.2;
}

.section-title-row {
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: center;
    gap: 1rem;
}

.page-section > p,
.page-section > ul,
.page-section > ol {
    font-size: 0.92rem;
    line-height: 1.8;
    color: #333;
}

/* ── OVERVIEW CARDS ───────────────────────────── */
.card-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1px;
    background: var(--gray-2);
    border: 1px solid var(--gray-2);
}

.card {
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: 0.45rem;
    padding: 1.4rem 1.25rem;
    background: #fff;
    border-left: 3px solid transparent;
    transition: border-color 0.15s, background 0.15s;
}

.card:hover {
    border-left-color: var(--accent);
    background: #fffaf7;
}

.card-icon {
    font-size: 1rem;
    color: var(--accent);
    opacity: 0.8;
}

.card h3 {
    font-size: 0.88rem;
    font-weight: 700;
    color: var(--navy);
    line-height: 1.3;
}

.card p {
    font-size: 0.82rem;
    color: #666;
    line-height: 1.65;
    flex: 1;
}

/* ── STREAM CARDS ─────────────────────────────── */
.stream-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.stream-card {
    min-width: 0;
    display: grid;
    gap: 0.6rem;
    padding: 1.25rem;
    background: var(--gray-1);
    border-left: 4px solid var(--gray-2);
}

.stream-card.cspl   { border-left-color: var(--cspl); }
.stream-card.vlsi   { border-left-color: var(--vlsi); }
.stream-card.peps   { border-left-color: var(--peps); }
.stream-card.syscon { border-left-color: var(--syscon); }

.stream-tag {
    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.stream-tag.cspl   { color: var(--cspl); }
.stream-tag.vlsi   { color: var(--vlsi); }
.stream-tag.peps   { color: var(--peps); }
.stream-tag.syscon { color: var(--syscon); }

.stream-card h3 {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--navy);
    line-height: 1.3;
}

.stream-card p,
.stream-card li {
    font-size: 0.84rem;
    color: #444;
    line-height: 1.7;
}

.stream-card ul {
    padding-left: 1.1rem;
    display: grid;
    gap: 0.3rem;
}

/* ── GUIDELINE BLOCKS (numbered) ─────────────── */
.block {
    min-width: 0;
    border: 1px solid var(--gray-2);
    overflow: hidden;
}

.block-header {
    display: grid;
    grid-template-columns: 52px 1fr;
    align-items: center;
    background: var(--navy);
    padding: 0.85rem 1.25rem;
    gap: 0.75rem;
}

.block-num {
    font-size: 1.3rem;
    font-weight: 700;
    color: rgba(255,255,255,0.25);
    text-align: center;
    line-height: 1;
}

.block-header h3 {
    font-size: 0.95rem;
    font-weight: 700;
    color: #ffffff;
}

.block-body {
    display: grid;
    gap: 1rem;
    padding: 1.25rem;
    background: #ffffff;
}

.block-body > p {
    font-size: 0.9rem;
    line-height: 1.8;
    color: #333;
}

/* ── INFO ROWS (label + value) ────────────────── */
.info-table {
    min-width: 0;
    border: 1px solid var(--gray-2);
    overflow: hidden;
}

.info-row {
    display: grid;
    grid-template-columns: minmax(100px, 160px) 1fr;
    gap: 1rem;
    padding: 0.65rem 1rem;
    border-bottom: 1px solid var(--gray-2);
    align-items: start;
    min-width: 0;
}

.info-row:last-child { border-bottom: none; }

.info-label {
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--accent);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    line-height: 1.5;
    word-break: break-word;
}

.info-value {
    font-size: 0.85rem;
    color: #333;
    line-height: 1.6;
    min-width: 0;
    word-break: break-word;
}

/* ── FILTER BAR (faculty, listings) ──────────── */
.filter-bar {
    background: var(--gray-1);
    border-bottom: 1px solid var(--gray-2);
    padding: 0 var(--page-pad);
    position: sticky;
    top: var(--nav-height);
    z-index: 100;
}

.filter-inner {
    display: flex;
    flex-wrap: wrap;
    max-width: var(--max-w);
    margin: 0 auto;
}

.filter-btn {
    background: none;
    border: none;
    border-bottom: 3px solid transparent;
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--gray-3);
    padding: 0.85rem 1.1rem;
    letter-spacing: 0.03em;
    transition: color 0.15s, border-color 0.15s;
    white-space: nowrap;
}

.filter-btn:hover          { color: var(--navy); }
.filter-btn.active         { color: var(--navy); border-bottom-color: var(--navy); }
.filter-btn.cspl.active    { color: var(--cspl);   border-bottom-color: var(--cspl); }
.filter-btn.vlsi.active    { color: var(--vlsi);   border-bottom-color: var(--vlsi); }
.filter-btn.peps.active    { color: var(--peps);   border-bottom-color: var(--peps); }
.filter-btn.syscon.active  { color: var(--syscon); border-bottom-color: var(--syscon); }

/* ── LISTING PAGE BODY (faculty, staff etc.) ──── */
.listing-body {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 3rem var(--page-pad);
}

/* ── BUTTONS ──────────────────────────────────── */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.85rem;
    font-weight: 600;
    padding: 0.65rem 1.3rem;
    text-decoration: none;
    letter-spacing: 0.03em;
    transition: background 0.15s, color 0.15s;
    border: none;
}

.btn-primary {
    background: var(--navy);
    color: #ffffff;
}

.btn-primary:hover {
    background: var(--accent);
    color: #ffffff;
    text-decoration: none;
}

.btn-outline {
    background: transparent;
    color: var(--navy);
    border: 1px solid var(--gray-2);
}

.btn-outline:hover {
    background: var(--navy);
    color: #ffffff;
    border-color: var(--navy);
    text-decoration: none;
}

/* ── INLINE ELEMENTS ──────────────────────────── */
.inline-link {
    color: var(--accent);
    text-decoration: underline;
}

.inline-link:hover { color: var(--navy); }

.note-box {
    font-size: 0.85rem;
    color: #555;
    background: #fff8f0;
    border-left: 3px solid var(--accent);
    padding: 0.75rem 1rem;
    line-height: 1.6;
}

.coming-soon {
    font-size: 0.88rem;
    color: var(--gray-3);
    font-style: italic;
}

/* ── RESPONSIVE ───────────────────────────────── */
@media (max-width: 900px) {
    .page-body {
        grid-template-columns: 1fr;
        padding: 2rem 1.5rem;
    }

    .page-sidebar {
        position: static;
        border-bottom: 1px solid var(--gray-2);
        padding-bottom: 1.25rem;
    }

    .stream-grid {
        grid-template-columns: 1fr;
    }

    .card-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {
    .info-row {
        grid-template-columns: 1fr;
        gap: 0.15rem;
    }

    .block-header {
        grid-template-columns: 40px 1fr;
    }

    .page-hero {
        padding: 2.5rem 1.25rem;
    }
}