/* ============================================
   智寻研途 | 留学导师探索AI智能体
   Modern Tech Aesthetic - Dark Space Theme
   ============================================ */

/* CSS Variables */
:root {
    /* Colors */
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: rgba(20, 20, 30, 0.6);
    --bg-card-hover: rgba(30, 30, 45, 0.7);

    --accent-cyan: #00d4ff;
    --accent-purple: #a855f7;
    --accent-pink: #ec4899;
    --accent-gradient: linear-gradient(135deg, var(--accent-cyan), var(--accent-purple));

    --text-primary: #f0f0f5;
    --text-secondary: #9090a0;
    --text-muted: #606070;

    --border-subtle: rgba(255, 255, 255, 0.06);
    --border-glow: rgba(0, 212, 255, 0.3);

    --glow-cyan: 0 0 30px rgba(0, 212, 255, 0.3);
    --glow-purple: 0 0 30px rgba(168, 85, 247, 0.3);

    /* Typography */
    --font-display: 'Syne', sans-serif;
    --font-body: 'Outfit', sans-serif;

    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 5rem;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-weight: 400;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ============================================
   Animated Background
   ============================================ */
.bg-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.gradient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.4;
    animation: float 20s ease-in-out infinite;
}

.orb-1 {
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, var(--accent-cyan) 0%, transparent 70%);
    top: -200px;
    right: -100px;
    animation-delay: 0s;
}

.orb-2 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, var(--accent-purple) 0%, transparent 70%);
    bottom: -150px;
    left: -100px;
    animation-delay: -7s;
}

.orb-3 {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, var(--accent-pink) 0%, transparent 70%);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation-delay: -14s;
    opacity: 0.2;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
    }
    25% {
        transform: translate(50px, -30px) scale(1.05);
    }
    50% {
        transform: translate(-20px, 40px) scale(0.95);
    }
    75% {
        transform: translate(-40px, -20px) scale(1.02);
    }
}

.noise-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
    opacity: 0.03;
    pointer-events: none;
}

.grid-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        linear-gradient(rgba(255,255,255,0.02) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,0.02) 1px, transparent 1px);
    background-size: 60px 60px;
    pointer-events: none;
}

/* ============================================
   Navigation
   ============================================ */
.nav-bar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 var(--space-xl);
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-subtle);
    z-index: 100;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    cursor: pointer;
    transition: transform var(--transition-fast);
    padding: var(--space-xs) 0;
}

.nav-logo:hover {
    transform: translateY(-1px);
}

.logo-icon-wrapper {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 46px;
    height: 46px;
    position: relative;
}

.logo-icon {
    width: 100%;
    height: 100%;
    transition: all var(--transition-base);
    filter: drop-shadow(0 0 8px rgba(0, 212, 255, 0.3));
}

.nav-logo:hover .logo-icon {
    transform: scale(1.1) rotate(5deg);
    filter: drop-shadow(0 0 12px rgba(0, 212, 255, 0.5));
}

.nav-logo:hover .logo-icon circle,
.nav-logo:hover .logo-icon path,
.nav-logo:hover .logo-icon line,
.nav-logo:hover .logo-icon .logo-center-text {
    animation: logoGlow 2s ease-in-out infinite;
}

.logo-icon .logo-center-text {
    font-weight: 700;
    transition: all var(--transition-base);
}

.nav-logo:hover .logo-icon .logo-center-text {
    transform: scale(1.05);
}

@keyframes logoGlow {
    0%, 100% {
        opacity: 0.8;
    }
    50% {
        opacity: 1;
    }
}

.logo-text-container {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    line-height: 1.2;
    gap: 0.1rem;
    justify-content: center;
    position: relative;
}

.logo-text-cn {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text-primary);
    background: linear-gradient(135deg, var(--text-primary) 0%, rgba(240, 240, 245, 0.95) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transition: all var(--transition-base);
    position: relative;
}

.nav-logo:hover .logo-text-cn {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-text-en {
    font-family: var(--font-body);
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--text-secondary);
    opacity: 0.85;
    position: relative;
    padding-left: 0.2rem;
    transition: all var(--transition-base);
    margin-top: -0.05rem;
}

.logo-text-en::before {
    content: '';
    position: absolute;
    left: -0.1rem;
    top: 50%;
    transform: translateY(-50%);
    width: 1.5px;
    height: 65%;
    background: linear-gradient(180deg, 
        transparent 0%, 
        var(--accent-cyan) 50%, 
        transparent 100%);
    opacity: 0.5;
    transition: opacity var(--transition-fast);
}

.nav-logo:hover .logo-text-en {
    color: var(--accent-cyan);
    opacity: 1;
}

.nav-logo:hover .logo-text-en::before {
    opacity: 0.8;
    width: 2px;
}

.nav-links {
    display: flex;
    gap: var(--space-lg);
}

.nav-link {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.nav-link:hover {
    color: var(--text-primary);
}

.nav-link.active {
    color: var(--accent-cyan);
    background: rgba(0, 212, 255, 0.1);
}

.nav-status {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.status-dot {
    width: 8px;
    height: 8px;
    background: #22c55e;
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.6; transform: scale(1.1); }
}

/* Language Toggle */
.lang-toggle {
    display: flex;
    align-items: center;
    gap: 2px;
    padding: 3px;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
}

.lang-btn {
    padding: 6px 12px;
    background: transparent;
    border: none;
    border-radius: 6px;
    font-family: var(--font-body);
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-muted);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.lang-btn:hover {
    color: var(--text-secondary);
}

.lang-btn.active {
    background: var(--accent-gradient);
    color: var(--bg-primary);
    font-weight: 600;
}

/* ============================================
   Main Content
   ============================================ */
.main-content {
    padding-top: 72px;
    min-height: 100vh;
}

/* ============================================
   Hero Section
   ============================================ */
.hero-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: calc(100vh - 72px);
    padding: var(--space-3xl) var(--space-xl);
    text-align: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    background: rgba(168, 85, 247, 0.1);
    border: 1px solid rgba(168, 85, 247, 0.2);
    border-radius: 100px;
    font-size: 0.85rem;
    color: var(--accent-purple);
    margin-bottom: var(--space-xl);
    animation: fadeInUp 0.6s ease backwards;
}

.badge-icon {
    animation: sparkle 2s ease-in-out infinite;
}

@keyframes sparkle {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.7; transform: scale(1.2); }
}

.hero-title {
    font-family: var(--font-display);
    font-size: clamp(2.5rem, 8vw, 5rem);
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.03em;
    margin-bottom: var(--space-lg);
}

.title-line {
    display: block;
    animation: fadeInUp 0.6s ease backwards;
}

.title-line:nth-child(1) { animation-delay: 0.1s; }
.title-line:nth-child(2) { animation-delay: 0.2s; }

.gradient-text {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 500px;
    margin-bottom: var(--space-2xl);
    animation: fadeInUp 0.6s ease 0.3s backwards;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ============================================
   Glass Card
   ============================================ */
.glass-card {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
}

.glass-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-glow);
    box-shadow: var(--glow-cyan);
}

/* ============================================
   Search Box
   ============================================ */
.search-container {
    width: 100%;
    max-width: 700px;
    animation: fadeInUp 0.6s ease 0.4s backwards;
}

.search-box {
    position: relative;
    padding: var(--space-lg);
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.search-icon {
    position: absolute;
    top: var(--space-lg);
    left: var(--space-lg);
    color: var(--text-muted);
}

.search-input {
    width: 100%;
    padding: var(--space-md);
    padding-left: calc(var(--space-lg) + 24px);
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-md);
    font-family: var(--font-body);
    font-size: 1rem;
    color: var(--text-primary);
    resize: none;
    transition: all var(--transition-fast);
}

.search-input::placeholder {
    color: var(--text-muted);
}

.search-input:focus {
    outline: none;
    border-color: var(--accent-cyan);
    box-shadow: 0 0 0 3px rgba(0, 212, 255, 0.1);
}

.search-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    background: var(--accent-gradient);
    border: none;
    border-radius: var(--radius-md);
    font-family: var(--font-body);
    font-size: 1rem;
    font-weight: 600;
    color: var(--bg-primary);
    cursor: pointer;
    transition: all var(--transition-base);
}

.search-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--glow-cyan);
}

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

.btn-icon {
    font-size: 1.2rem;
    transition: transform var(--transition-fast);
}

.search-btn:hover .btn-icon {
    transform: translateX(4px);
}

/* Quick Tags */
.quick-tags {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--space-sm);
    margin-top: var(--space-md);
    justify-content: center;
}

.quick-tags:first-of-type {
    margin-top: var(--space-lg);
}

.tag-label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.quick-tag {
    padding: var(--space-xs) var(--space-md);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-subtle);
    border-radius: 100px;
    font-family: var(--font-body);
    font-size: 0.85rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.quick-tag:hover {
    background: rgba(0, 212, 255, 0.1);
    border-color: var(--accent-cyan);
    color: var(--accent-cyan);
}

.quick-tag.selected {
    background: rgba(0, 212, 255, 0.15);
    border-color: var(--accent-cyan);
    color: var(--accent-cyan);
    box-shadow: 0 0 10px rgba(0, 212, 255, 0.3);
}

.quick-tag.selected:hover {
    background: rgba(0, 212, 255, 0.2);
    box-shadow: 0 0 15px rgba(0, 212, 255, 0.4);
}

/* ============================================
   Loading Section
   ============================================ */
.loading-section {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: calc(100vh - 72px);
    padding: var(--space-xl);
}

.loading-container {
    text-align: center;
    padding: var(--space-3xl) var(--space-2xl);
    max-width: 500px;
}

.loading-animation {
    position: relative;
    width: 120px;
    height: 120px;
    margin: 0 auto var(--space-xl);
}

.orbit-ring {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    border: 1px solid rgba(0, 212, 255, 0.2);
    border-radius: 50%;
}

.ring-1 {
    width: 120px;
    height: 120px;
    animation: orbit 3s linear infinite;
}

.ring-2 {
    width: 80px;
    height: 80px;
    animation: orbit 2s linear infinite reverse;
}

.ring-3 {
    width: 40px;
    height: 40px;
    animation: orbit 1.5s linear infinite;
}

@keyframes orbit {
    from { transform: translate(-50%, -50%) rotate(0deg); }
    to { transform: translate(-50%, -50%) rotate(360deg); }
}

.orbit-dot {
    position: absolute;
    top: -4px;
    left: 50%;
    transform: translateX(-50%);
    width: 8px;
    height: 8px;
    background: var(--accent-cyan);
    border-radius: 50%;
    box-shadow: var(--glow-cyan);
}

.core-pulse {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 20px;
    height: 20px;
    background: var(--accent-gradient);
    border-radius: 50%;
    animation: corePulse 1.5s ease-in-out infinite;
}

@keyframes corePulse {
    0%, 100% {
        transform: translate(-50%, -50%) scale(1);
        box-shadow: 0 0 20px rgba(0, 212, 255, 0.5);
    }
    50% {
        transform: translate(-50%, -50%) scale(1.2);
        box-shadow: 0 0 40px rgba(0, 212, 255, 0.8);
    }
}

.loading-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.loading-status {
    color: var(--text-secondary);
    margin-bottom: var(--space-lg);
}

.cancel-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    margin: var(--space-md) auto;
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: var(--radius-md);
    font-family: var(--font-body);
    font-size: 0.95rem;
    font-weight: 500;
    color: #ef4444;
    cursor: pointer;
    transition: all var(--transition-base);
}

.cancel-btn:hover {
    background: rgba(239, 68, 68, 0.2);
    border-color: rgba(239, 68, 68, 0.5);
    transform: translateY(-2px);
    box-shadow: 0 4px 20px rgba(239, 68, 68, 0.3);
}

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

.cancel-icon {
    font-size: 1.1rem;
}

.loading-progress {
    width: 100%;
    height: 4px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 100px;
    overflow: hidden;
    margin-bottom: var(--space-xl);
}

.progress-bar {
    height: 100%;
    width: 0%;
    background: var(--accent-gradient);
    border-radius: 100px;
    transition: width 0.3s ease;
}

.loading-steps {
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
}

.step {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
    font-size: 0.8rem;
    color: var(--text-muted);
    opacity: 0.5;
    transition: all var(--transition-base);
}

.step.active {
    opacity: 1;
    color: var(--accent-cyan);
}

.step.completed {
    opacity: 1;
    color: #22c55e;
}

.step-icon {
    font-size: 1rem;
}

.step.active .step-icon {
    animation: sparkle 1s ease-in-out infinite;
}

/* ============================================
   Results Section
   ============================================ */
.results-section {
    padding: var(--space-2xl) var(--space-xl);
    max-width: 1400px;
    margin: 0 auto;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--space-xl);
    flex-wrap: wrap;
    gap: var(--space-md);
}

.results-title {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
}

.results-count {
    color: var(--text-secondary);
    margin-top: var(--space-xs);
}

.results-count span {
    color: var(--accent-cyan);
    font-weight: 600;
}

.results-actions {
    display: flex;
    gap: var(--space-md);
}

.action-btn {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    border-radius: var(--radius-md);
    font-family: var(--font-body);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.action-btn.secondary {
    background: transparent;
    border: 1px solid var(--border-subtle);
    color: var(--text-secondary);
}

.action-btn.secondary:hover {
    border-color: var(--text-secondary);
    color: var(--text-primary);
}

.action-btn.primary {
    background: var(--accent-gradient);
    border: none;
    color: var(--bg-primary);
}

.action-btn.primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--glow-cyan);
}

/* ============================================
   Professor Cards
   ============================================ */
.professors-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: var(--space-lg);
    margin-bottom: var(--space-2xl);
}

.professor-card {
    padding: var(--space-lg);
    animation: fadeInUp 0.5s ease backwards;
}

.professor-card:nth-child(1) { animation-delay: 0.05s; }
.professor-card:nth-child(2) { animation-delay: 0.1s; }
.professor-card:nth-child(3) { animation-delay: 0.15s; }
.professor-card:nth-child(4) { animation-delay: 0.2s; }
.professor-card:nth-child(5) { animation-delay: 0.25s; }
.professor-card:nth-child(6) { animation-delay: 0.3s; }

.card-header {
    display: flex;
    align-items: flex-start;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
}

.card-avatar {
    width: 56px;
    height: 56px;
    background: var(--accent-gradient);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-display);
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--bg-primary);
    flex-shrink: 0;
}

.card-info {
    flex: 1;
    min-width: 0;
}

.professor-name {
    font-family: var(--font-display);
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: var(--space-xs);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.professor-university {
    font-size: 0.9rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.university-icon {
    color: var(--accent-purple);
}

.card-department {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: var(--space-md);
    padding-left: calc(56px + var(--space-md));
}

.card-research {
    margin-bottom: var(--space-md);
}

.research-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: var(--space-sm);
}

.research-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
}

.research-tag {
    padding: var(--space-xs) var(--space-sm);
    background: rgba(0, 212, 255, 0.1);
    border-radius: 100px;
    font-size: 0.8rem;
    color: var(--accent-cyan);
}

.card-notes-section {
    margin-bottom: var(--space-md);
    background: rgba(0, 212, 255, 0.05);
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--accent-cyan);
    overflow: hidden;
}

.notes-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-sm) var(--space-md);
    cursor: pointer;
    user-select: none;
    transition: background var(--transition-fast);
}

.notes-header:hover {
    background: rgba(0, 212, 255, 0.1);
}

.notes-label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--accent-cyan);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin: 0;
}

.notes-toggle {
    font-size: 0.7rem;
    color: var(--accent-cyan);
    transition: transform var(--transition-fast);
}

.card-notes {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
    white-space: pre-wrap;
    word-wrap: break-word;
    padding: 0 var(--space-md) var(--space-md);
    max-height: 200px;
    overflow: hidden;
    transition: max-height var(--transition-fast), padding var(--transition-fast);
}

.card-notes.collapsed {
    max-height: 0;
    padding: 0 var(--space-md);
}

.card-footer {
    display: flex;
    gap: var(--space-sm);
    padding-top: var(--space-md);
    border-top: 1px solid var(--border-subtle);
}

.contact-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    padding: var(--space-sm);
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
    font-family: var(--font-body);
    font-size: 0.85rem;
    color: var(--text-secondary);
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.contact-btn:hover {
    background: rgba(0, 212, 255, 0.1);
    border-color: var(--accent-cyan);
    color: var(--accent-cyan);
}

.contact-btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.contact-btn.scholar-btn {
    background: rgba(66, 133, 244, 0.1);
    border-color: rgba(66, 133, 244, 0.3);
}

.contact-btn.scholar-btn:hover {
    background: rgba(66, 133, 244, 0.2);
    border-color: rgba(66, 133, 244, 0.5);
    color: #4285f4;
}

/* ============================================
   AI Summary
   ============================================ */
.ai-summary {
    padding: var(--space-xl);
}

.summary-header {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-md);
}

.summary-icon {
    font-size: 1.2rem;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.summary-header h3 {
    font-family: var(--font-display);
    font-size: 1.1rem;
    font-weight: 600;
}

.summary-text {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    padding: var(--space-xl);
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    border-top: 1px solid var(--border-subtle);
}

/* ============================================
   Utility Classes
   ============================================ */
.hidden {
    display: none !important;
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .hero-section {
        padding: var(--space-2xl) var(--space-md);
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .search-container {
        padding: 0 var(--space-sm);
    }

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

    .results-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .loading-steps {
        flex-wrap: wrap;
    }
}

/* ============================================
   Scrollbar
   ============================================ */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 100px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}

/* ============================================
   Selection
   ============================================ */
::selection {
    background: rgba(0, 212, 255, 0.3);
    color: var(--text-primary);
}