/* ============================================
   ASHKAN TASHK — PERSONAL ACADEMIC WEBSITE
   Light / Dark mode · Fluid typography · Sidebar
   ============================================ */

/* ══════════════════════════════════════
   THEME VARIABLES — Dark (default)
   ══════════════════════════════════════ */
:root {
    /* Dark theme colors */
    --color-bg:         #0d1b16;
    --color-bg-alt:     #132920;
    --color-surface:    #1a3a2e;
    --color-surface-2:  #1f4436;
    --color-border:     #2a5a48;
    --color-accent:     #5ce0b8;
    --color-accent-dim: #3aad8a;
    --color-accent-glow: rgba(92, 224, 184, 0.12);
    --color-text:       #e8ede9;
    --color-text-dim:   #9bb5a8;
    --color-text-muted: #6d8f7e;
    --color-white:      #ffffff;
    --color-card-hover: rgba(92, 224, 184, 0.04);
    --shadow-card:      0 2px 8px rgba(0,0,0,0.25);
    --shadow-photo:     0 8px 24px rgba(0,0,0,0.4);
    --pub-thumb-bg:     #0d1b16;
    --nav-bg:           rgba(13, 27, 22, 0.92);
    --nav-border:       rgba(42, 90, 72, 0.3);
    --toggle-icon-show-dark: none;
    --toggle-icon-show-light: block;

    /* Fonts */
    --font-display: 'DM Serif Display', Georgia, serif;
    --font-body:    'Source Sans 3', 'Segoe UI', sans-serif;
    --font-mono:    'JetBrains Mono', 'Fira Code', monospace;

    /* Structural */
    --sidebar-width: 260px;
    --nav-height: 56px;
    --radius: 10px;
    --transition: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);

    /* ── Fluid type scale ──
       Uses clamp(min, preferred, max) so font sizes
       scale smoothly between viewport widths. */
    --fs-xs:    clamp(0.62rem, 0.55rem + 0.25vw, 0.72rem);
    --fs-sm:    clamp(0.72rem, 0.65rem + 0.3vw,  0.85rem);
    --fs-base:  clamp(0.85rem, 0.78rem + 0.35vw, 1rem);
    --fs-md:    clamp(0.92rem, 0.82rem + 0.4vw,  1.08rem);
    --fs-lg:    clamp(1.05rem, 0.9rem  + 0.5vw,  1.25rem);
    --fs-xl:    clamp(1.2rem,  1rem    + 0.7vw,  1.55rem);
    --fs-2xl:   clamp(1.4rem,  1.1rem  + 1vw,    1.85rem);

    /* Fluid spacing */
    --sp-xs:  clamp(4px,  0.3vw,  6px);
    --sp-sm:  clamp(6px,  0.5vw,  10px);
    --sp-md:  clamp(10px, 0.8vw,  16px);
    --sp-lg:  clamp(14px, 1.2vw,  24px);
    --sp-xl:  clamp(18px, 1.6vw,  32px);
}

/* ══════════════════════════════════════
   LIGHT THEME
   ══════════════════════════════════════ */
[data-theme="light"] {
    --color-bg:         #f4f6f5;
    --color-bg-alt:     #eaf0ed;
    --color-surface:    #ffffff;
    --color-surface-2:  #f0f5f2;
    --color-border:     #c8d9cf;
    --color-accent:     #1a8a64;
    --color-accent-dim: #22a87a;
    --color-accent-glow: rgba(26, 138, 100, 0.08);
    --color-text:       #1a2e24;
    --color-text-dim:   #3d5c4c;
    --color-text-muted: #7a9588;
    --color-white:      #0d1b16;
    --color-card-hover: rgba(26, 138, 100, 0.04);
    --shadow-card:      0 2px 10px rgba(0,0,0,0.06);
    --shadow-photo:     0 6px 20px rgba(0,0,0,0.1);
    --pub-thumb-bg:     #eaf0ed;
    --nav-bg:           rgba(244, 246, 245, 0.92);
    --nav-border:       rgba(200, 217, 207, 0.6);
    --toggle-icon-show-dark: block;
    --toggle-icon-show-light: none;
}


/* ── RESET ── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: calc(var(--nav-height) + 16px); }

body {
    font-family: var(--font-body);
    font-size: var(--fs-base);
    line-height: 1.7;
    color: var(--color-text);
    background: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
    transition: background 0.4s ease, color 0.4s ease;
}

a { color: var(--color-accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-white); }
ul { list-style: none; }

/* CRITICAL: lock all images/SVGs to container */
img, svg { max-width: 100%; height: auto; display: block; }


/* ══════════════════════════════════════
   NAVIGATION
   ══════════════════════════════════════ */
#main-nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    height: var(--nav-height);
    background: var(--nav-bg);
    backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--nav-border);
    transition: background 0.4s ease, border-color 0.4s ease;
}
.nav-inner {
    max-width: 1300px; margin: 0 auto;
    padding: 0 clamp(14px, 2vw, 24px);
    display: flex; align-items: center; justify-content: space-between;
    height: 100%;
}
.nav-brand {
    font-family: var(--font-display); font-size: var(--fs-lg);
    color: var(--color-accent); letter-spacing: 0.01em;
}
.nav-links { display: flex; gap: clamp(10px, 1.5vw, 20px); align-items: center; }
.nav-links a {
    font-size: var(--fs-xs); font-weight: 500; color: var(--color-text-dim);
    letter-spacing: 0.04em; text-transform: uppercase; padding: 4px 0;
    position: relative;
}
.nav-links a::after {
    content: ''; position: absolute; bottom: -2px; left: 0;
    width: 0; height: 2px; background: var(--color-accent);
    transition: width var(--transition);
}
.nav-links a:hover,
.nav-links a.nav-active { color: var(--color-accent); }
.nav-links a:hover::after,
.nav-links a.nav-active::after { width: 100%; }

/* Theme toggle button in nav */
.theme-toggle {
    display: flex; align-items: center; justify-content: center;
    width: 34px; height: 34px; border-radius: 50%;
    background: var(--color-surface-2); border: 1px solid var(--color-border);
    cursor: pointer; color: var(--color-accent);
    transition: all var(--transition); margin-left: clamp(6px, 1vw, 12px);
}
.theme-toggle:hover { background: var(--color-accent); color: var(--color-bg); }
.theme-toggle svg { width: 18px; height: 18px; flex-shrink: 0; }
.icon-sun  { display: var(--toggle-icon-show-dark); }
.icon-moon { display: var(--toggle-icon-show-light); }

/* Mobile nav toggle */
.nav-toggle {
    display: none; flex-direction: column; gap: 5px;
    background: none; border: none; cursor: pointer; padding: 6px;
}
.nav-toggle span {
    width: 22px; height: 2px; background: var(--color-text);
    border-radius: 2px; transition: var(--transition);
}


/* ══════════════════════════════════════
   PAGE WRAPPER — SIDEBAR + MAIN
   ══════════════════════════════════════ */
.page-wrapper {
    display: flex; max-width: 1300px; margin: 0 auto;
    padding-top: var(--nav-height); min-height: 100vh;
}


/* ══════════════════════════════════════
   LEFT SIDEBAR
   ══════════════════════════════════════ */
.sidebar {
    width: var(--sidebar-width); flex-shrink: 0;
    padding: var(--sp-lg) clamp(12px, 1.5vw, 20px);
}
.sidebar-sticky {
    position: sticky; top: calc(var(--nav-height) + 20px);
    text-align: center;
    background: var(--color-surface); border-radius: var(--radius);
    padding: var(--sp-xl) clamp(12px, 1.2vw, 18px) var(--sp-lg);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-card);
    transition: background 0.4s ease, border-color 0.4s ease, box-shadow 0.4s ease;
}

/* Profile photo — fluid but capped */
.profile-photo {
    width: clamp(100px, 12vw, 140px);
    height: clamp(100px, 12vw, 140px);
    margin: 0 auto var(--sp-md);
    border-radius: 50%; overflow: hidden;
    border: 3px solid var(--color-border);
    background: var(--color-surface-2);
    box-shadow: var(--shadow-photo);
}
.profile-photo img {
    width: 100%; height: 100%;
    object-fit: cover; object-position: center top;
}

.profile-name {
    font-family: var(--font-display); font-size: var(--fs-lg);
    color: var(--color-white); margin-bottom: 2px;
}
.profile-title { font-size: var(--fs-sm); color: var(--color-accent); margin-bottom: 0; }
.profile-affil { font-size: var(--fs-xs); color: var(--color-text-muted); margin-bottom: var(--sp-md); }

/* Social icons */
.profile-links {
    display: flex; justify-content: center; gap: clamp(8px, 0.8vw, 12px);
    margin-bottom: var(--sp-md); padding-bottom: var(--sp-md);
    border-bottom: 1px solid var(--color-border);
}
.profile-links a {
    display: flex; align-items: center; justify-content: center;
    width: clamp(30px, 3vw, 36px); height: clamp(30px, 3vw, 36px);
    border-radius: 50%; background: var(--color-surface-2);
    color: var(--color-text-dim); transition: all var(--transition);
}
.profile-links a:hover { background: var(--color-accent); color: var(--color-bg); }
.profile-links svg { width: clamp(16px, 1.8vw, 22px); height: clamp(16px, 1.8vw, 22px); flex-shrink: 0; }

/* Sidebar info */
.sidebar-info { text-align: left; }
.sidebar-section { margin-bottom: var(--sp-md); }
.sidebar-section:last-child { margin-bottom: 0; }
.sidebar-section h4 {
    font-family: var(--font-mono); font-size: var(--fs-xs);
    color: var(--color-accent); text-transform: uppercase;
    letter-spacing: 0.08em; margin-bottom: var(--sp-xs);
}
.sidebar-section p { font-size: var(--fs-sm); color: var(--color-text-dim); line-height: 1.5; }
.sidebar-section li { font-size: var(--fs-sm); color: var(--color-text-dim); line-height: 1.5; padding: 2px 0; }


/* ══════════════════════════════════════
   MAIN CONTENT
   ══════════════════════════════════════ */
.main-content {
    flex: 1; min-width: 0;
    padding: var(--sp-lg) var(--sp-lg) var(--sp-lg) var(--sp-xl);
}

/* Cards */
.card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: clamp(18px, 2.2vw, 28px);
    margin-bottom: clamp(14px, 1.5vw, 20px);
    overflow: hidden;
    box-shadow: var(--shadow-card);
    transition: background 0.4s ease, border-color 0.4s ease, box-shadow 0.4s ease;
}
.card h3 {
    font-family: var(--font-display); font-size: var(--fs-2xl);
    color: var(--color-white); margin-bottom: var(--sp-md);
}
.card > p {
    color: var(--color-text-dim); margin-bottom: var(--sp-sm);
    font-size: var(--fs-md); text-align: justify;
}
.card > p:last-of-type { margin-bottom: 0; }
.card em { color: var(--color-accent); font-style: italic; }
.section-intro { margin-bottom: var(--sp-lg) !important; }


/* ── Highlight box ── */
.highlight-box {
    background: var(--color-surface-2); border: 1px solid var(--color-border);
    border-radius: 8px; padding: clamp(16px, 1.8vw, 22px); margin-bottom: var(--sp-lg);
    transition: background 0.4s ease, border-color 0.4s ease;
}
.highlight-label {
    display: inline-block; font-family: var(--font-mono); font-size: var(--fs-xs);
    color: var(--color-accent); text-transform: uppercase;
    letter-spacing: 0.08em; margin-bottom: var(--sp-xs);
}
.highlight-box h4 {
    font-family: var(--font-display); font-size: var(--fs-xl);
    color: var(--color-white); margin-bottom: var(--sp-sm); font-style: italic;
}
.highlight-box p { font-size: var(--fs-base); color: var(--color-text-dim); line-height: 1.65; }

/* Research topics bullet list inside highlight box */
.research-subtopic-heading {
    font-family: var(--font-display); font-size: var(--fs-lg);
    color: var(--color-white); margin-top: var(--sp-lg); margin-bottom: var(--sp-sm);
    font-style: normal;
}
.research-topics {
    list-style: none; padding: 0; margin: 0 0 var(--sp-lg) 0;
}
.research-topics li {
    font-size: var(--fs-sm); color: var(--color-text-dim); line-height: 1.65;
    padding: var(--sp-sm) 0;
    border-bottom: 1px solid var(--color-border);
    position: relative;
    padding-left: 1.2em;
}
.research-topics li::before {
    content: '▸'; position: absolute; left: 0; top: var(--sp-sm);
    color: var(--color-accent); font-size: var(--fs-sm);
}
.research-topics li:last-child { border-bottom: none; }
.research-topics li strong { color: var(--color-white); }

.funding-note {
    font-size: var(--fs-sm); color: var(--color-text-muted);
    padding-top: var(--sp-md);
    border-top: 1px solid var(--color-border);
    margin-top: var(--sp-sm);
}
.funding-note strong { color: var(--color-accent); }


/* ── Research grid ── */
.research-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: clamp(10px, 1.2vw, 16px); }
.research-card {
    background: var(--color-surface-2); border: 1px solid var(--color-border);
    border-radius: 8px; padding: clamp(14px, 1.5vw, 20px);
    transition: border-color var(--transition), background 0.4s ease;
}
.research-card:hover { border-color: var(--color-accent-dim); background: var(--color-card-hover); }
.research-card h4 {
    font-family: var(--font-display); font-size: var(--fs-md);
    color: var(--color-white); margin-bottom: var(--sp-xs);
}
.research-card p { font-size: var(--fs-sm); color: var(--color-text-dim); line-height: 1.6; margin-bottom: var(--sp-sm); }

.tag-row { display: flex; flex-wrap: wrap; gap: clamp(3px, 0.4vw, 5px); }
.tag {
    font-family: var(--font-mono); font-size: var(--fs-xs);
    padding: clamp(2px, 0.3vw, 3px) clamp(6px, 0.7vw, 9px);
    border-radius: 50px;
    background: var(--color-accent-glow); color: var(--color-accent-dim);
    border: 1px solid rgba(92, 224, 184, 0.15);
}

[data-theme="light"] .tag {
    background: rgba(26, 138, 100, 0.08);
    color: #1a7a5a;
    border-color: rgba(26, 138, 100, 0.2);
}


/* ── Tools grid ── */
.tools-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: clamp(10px, 1vw, 14px); }
.tool-category {
    background: var(--color-surface-2); border: 1px solid var(--color-border);
    border-radius: 8px; padding: clamp(12px, 1.2vw, 16px);
    transition: background 0.4s ease, border-color 0.4s ease;
}
.tool-category h4 {
    font-family: var(--font-display); font-size: var(--fs-base);
    color: var(--color-white); margin-bottom: var(--sp-sm);
}
.tool-items { display: flex; flex-wrap: wrap; gap: clamp(3px, 0.4vw, 5px); }
.tool-items span {
    font-family: var(--font-mono); font-size: var(--fs-xs);
    padding: clamp(2px, 0.3vw, 3px) clamp(6px, 0.7vw, 9px);
    border-radius: 4px;
    background: var(--color-bg); color: var(--color-text-dim);
    border: 1px solid var(--color-border);
}


/* ── Timeline ── */
.timeline { padding-left: clamp(18px, 2vw, 24px); position: relative; }
.timeline::before {
    content: ''; position: absolute;
    left: clamp(4px, 0.5vw, 6px); top: 6px; bottom: 6px;
    width: 2px; background: var(--color-border);
    transition: background 0.4s ease;
}
.timeline-item {
    position: relative; padding-bottom: var(--sp-lg);
    display: flex; gap: clamp(10px, 1.2vw, 16px);
}
.timeline-item:last-child { padding-bottom: 0; }
.timeline-marker {
    width: clamp(10px, 1vw, 12px); height: clamp(10px, 1vw, 12px);
    border-radius: 50%; flex-shrink: 0;
    margin-top: 5px; margin-left: calc(clamp(18px, 2vw, 24px) * -1 + clamp(4px, 0.5vw, 6px) - clamp(5px, 0.5vw, 6px) + 1px);
    background: var(--color-bg); border: 2px solid var(--color-accent-dim);
    position: relative; z-index: 1;
    transition: background 0.4s ease;
}
.timeline-marker.active {
    background: var(--color-accent); border-color: var(--color-accent);
    box-shadow: 0 0 0 4px var(--color-accent-glow);
}
.timeline-body { flex: 1; }
.timeline-date {
    font-family: var(--font-mono); font-size: var(--fs-xs);
    color: var(--color-accent); text-transform: uppercase; letter-spacing: 0.06em;
}
.timeline-body h4 {
    font-family: var(--font-display); font-size: var(--fs-md);
    color: var(--color-white); margin: 2px 0;
}
.timeline-body p { font-size: var(--fs-sm); color: var(--color-text-dim); }
.timeline-detail { font-size: var(--fs-xs) !important; color: var(--color-text-muted) !important; margin-top: 2px; }


/* ══════════════════════════════════════
   PUBLICATIONS — fluid thumbnails
   ══════════════════════════════════════ */
.pub-list { display: flex; flex-direction: column; gap: clamp(10px, 1vw, 14px); }
.pub-card {
    display: flex; align-items: stretch;
    background: var(--color-surface-2); border: 1px solid var(--color-border);
    border-radius: 8px; overflow: hidden;
    transition: border-color var(--transition), background 0.4s ease;
}
.pub-card:hover { border-color: var(--color-accent-dim); }

.pub-thumb {
    width: clamp(110px, 14vw, 160px);
    min-width: clamp(110px, 14vw, 160px);
    max-width: clamp(110px, 14vw, 160px);
    display: flex; align-items: center; justify-content: center;
    background: var(--pub-thumb-bg); overflow: hidden;
}
.pub-thumb img {
    width: 100%; height: 100%;
    object-fit: contain; padding: clamp(4px, 0.5vw, 6px);
    max-height: clamp(90px, 12vw, 140px);
}

.pub-info {
    padding: clamp(10px, 1.2vw, 14px) clamp(12px, 1.5vw, 16px);
    flex: 1; display: flex; flex-direction: column; justify-content: center;
}
.pub-year {
    font-family: var(--font-mono); font-size: var(--fs-xs);
    color: var(--color-accent); letter-spacing: 0.08em;
}
.pub-info h4 { font-size: var(--fs-sm); font-weight: 600; color: var(--color-text); margin: 3px 0; line-height: 1.4; }
.pub-info h4 a { color: var(--color-text); }
.pub-info h4 a:hover { color: var(--color-accent); }
.pub-venue { font-size: var(--fs-xs); color: var(--color-text-muted); font-style: italic; }
.pub-more { text-align: center; margin-top: var(--sp-md); }


/* ── Opportunities ── */
.oppo-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: clamp(10px, 1vw, 14px); margin-bottom: var(--sp-md); }
.oppo-card {
    background: var(--color-surface-2); border: 1px solid var(--color-border);
    border-radius: 8px; padding: clamp(14px, 1.5vw, 18px);
    transition: border-color var(--transition), background 0.4s ease;
}
.oppo-card:hover { border-color: var(--color-accent-dim); }
.oppo-level {
    display: inline-block; font-family: var(--font-mono); font-size: var(--fs-xs);
    color: var(--color-accent); text-transform: uppercase; letter-spacing: 0.06em;
    padding: 2px clamp(6px, 0.6vw, 8px);
    border: 1px solid rgba(92, 224, 184, 0.25); border-radius: 50px;
    margin-bottom: var(--sp-sm);
}
.oppo-card h4 {
    font-family: var(--font-display); font-size: var(--fs-md);
    color: var(--color-white); margin-bottom: var(--sp-xs);
}
.oppo-card p { font-size: var(--fs-sm); color: var(--color-text-dim); line-height: 1.55; }
.oppo-note {
    background: var(--color-accent-glow); border: 1px solid rgba(92, 224, 184, 0.2);
    border-radius: 8px; padding: clamp(12px, 1.2vw, 16px) clamp(16px, 1.5vw, 20px);
    font-size: var(--fs-sm); color: var(--color-text-dim);
}
.oppo-note strong { color: var(--color-accent); }


/* ── Teaching ── */
.teaching-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: clamp(10px, 1vw, 14px); }
.teaching-item {
    background: var(--color-surface-2); border: 1px solid var(--color-border);
    border-radius: 8px; padding: clamp(14px, 1.5vw, 18px);
    transition: background 0.4s ease, border-color 0.4s ease;
}
.teaching-item h4 {
    font-family: var(--font-display); font-size: var(--fs-md);
    color: var(--color-white); margin-bottom: var(--sp-xs);
}
.teaching-item p { font-size: var(--fs-sm); color: var(--color-text-dim); line-height: 1.55; }


/* ── Buttons ── */
.btn {
    display: inline-block;
    padding: clamp(8px, 0.8vw, 10px) clamp(16px, 1.6vw, 22px);
    border-radius: 6px;
    font-family: var(--font-body); font-size: var(--fs-sm); font-weight: 600;
    letter-spacing: 0.02em; transition: all var(--transition);
    cursor: pointer; border: none; margin-top: var(--sp-sm);
}
.btn-primary { background: var(--color-accent); color: var(--color-bg); }
.btn-primary:hover { background: var(--color-white); color: var(--color-bg); }
.btn-outline { background: transparent; color: var(--color-accent); border: 1.5px solid var(--color-accent); }
.btn-outline:hover { background: var(--color-accent); color: var(--color-bg); }


/* ══════════════════════════════════════
   FOOTER
   ══════════════════════════════════════ */
#contact {
    background: var(--color-bg-alt);
    border-top: 1px solid var(--color-border);
    padding: clamp(32px, 4vw, 48px) clamp(14px, 2vw, 24px) clamp(18px, 2vw, 24px);
    transition: background 0.4s ease, border-color 0.4s ease;
}
.footer-inner { max-width: 1300px; margin: 0 auto; }
.footer-inner h3 {
    font-family: var(--font-display); font-size: var(--fs-xl);
    color: var(--color-white); margin-bottom: var(--sp-sm);
}
.footer-inner > p { color: var(--color-text-dim); font-size: var(--fs-base); margin-bottom: var(--sp-xs); }
.footer-email {
    font-family: var(--font-mono); font-size: var(--fs-sm);
    color: var(--color-accent); margin-bottom: var(--sp-md);
}
.footer-links { display: flex; flex-wrap: wrap; gap: clamp(6px, 0.7vw, 10px); margin-bottom: var(--sp-xl); }
.footer-links a {
    display: inline-block;
    padding: clamp(6px, 0.6vw, 8px) clamp(10px, 1.2vw, 16px);
    border: 1px solid var(--color-border); border-radius: 6px;
    color: var(--color-text-dim); font-size: var(--fs-sm); font-weight: 500;
    transition: all var(--transition);
}
.footer-links a:hover {
    border-color: var(--color-accent); color: var(--color-accent);
    background: var(--color-accent-glow);
}
.footer-bottom { padding-top: var(--sp-md); border-top: 1px solid var(--color-border); }
.footer-bottom p { font-size: var(--fs-xs); color: var(--color-text-muted); }


/* ══════════════════════════════════════
   BACK TO TOP
   ══════════════════════════════════════ */
#back-to-top {
    position: fixed; bottom: clamp(16px, 2.5vw, 28px); right: clamp(16px, 2.5vw, 28px);
    z-index: 999;
    width: clamp(38px, 4vw, 44px); height: clamp(38px, 4vw, 44px);
    border-radius: 50%;
    background: var(--color-accent); color: var(--color-bg);
    border: none; cursor: pointer;
    display: flex; align-items: center; justify-content: center;
    box-shadow: 0 4px 16px rgba(0,0,0,0.3);
    opacity: 0; pointer-events: none; transform: translateY(12px);
    transition: opacity 0.3s ease, transform 0.3s ease, background var(--transition);
}
#back-to-top.visible { opacity: 1; pointer-events: auto; transform: translateY(0); }
#back-to-top:hover { background: var(--color-white); }
#back-to-top svg { width: clamp(16px, 1.8vw, 20px); height: clamp(16px, 1.8vw, 20px); flex-shrink: 0; }


/* ══════════════════════════════════════
   RESPONSIVE BREAKPOINTS
   ══════════════════════════════════════ */

/* Tablet */
@media (max-width: 1024px) {
    .research-grid, .oppo-grid, .tools-grid { grid-template-columns: 1fr; }
    .teaching-grid { grid-template-columns: 1fr 1fr; }
}

/* Small tablet / large phone */
@media (max-width: 860px) {
    .page-wrapper { flex-direction: column; }

    .sidebar { width: 100%; padding: var(--sp-md); }
    .sidebar-sticky {
        position: static;
        display: flex; flex-wrap: wrap; align-items: center; gap: var(--sp-md);
        text-align: left; padding: var(--sp-md);
    }
    .profile-photo { width: 80px; height: 80px; margin: 0; }
    .profile-photo img { width: 80px; height: 80px; }
    .profile-name { font-size: var(--fs-lg); width: auto; }
    .profile-title, .profile-affil { width: auto; }
    .sidebar-info { display: none; }
    .profile-links { border-bottom: none; padding-bottom: 0; margin-bottom: 0; }

    .main-content { padding: 0 var(--sp-md) var(--sp-md); }
    .teaching-grid { grid-template-columns: 1fr; }
}

/* Phone */
@media (max-width: 600px) {
    .nav-links {
        display: none; position: absolute; top: var(--nav-height);
        left: 0; right: 0; flex-direction: column;
        background: var(--nav-bg); backdrop-filter: blur(14px);
        padding: var(--sp-md); border-bottom: 1px solid var(--color-border);
        gap: var(--sp-xs);
    }
    .nav-links.active { display: flex; }
    .nav-toggle { display: flex; }

    .pub-card { flex-direction: column; }
    .pub-thumb {
        width: 100%; min-width: 100%; max-width: 100%;
        max-height: clamp(120px, 25vw, 180px);
    }
    .pub-thumb img { max-height: clamp(100px, 22vw, 160px); }
}

/* High-DPI / 4K screens — slightly larger base sizes */
@media (min-width: 1800px) {
    :root {
        --fs-xs:   0.78rem;
        --fs-sm:   0.9rem;
        --fs-base: 1.05rem;
        --fs-md:   1.12rem;
        --fs-lg:   1.3rem;
        --fs-xl:   1.6rem;
        --fs-2xl:  1.9rem;
    }
}


/* ── Subtle fade-in ── */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(12px); }
    to   { opacity: 1; transform: translateY(0); }
}
.card { animation: fadeIn 0.5s ease-out both; }