/* ============================
   Professor Directory - Styles
   Premium Modern UI Design
   ============================ */

:root {
    /* Colors */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #0ea5e9;
    --accent: #f59e0b;

    --bg-dark: #0f172a;
    --bg-card: #1e293b;
    --bg-card-hover: #334155;
    --bg-input: #1e293b;

    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;

    --border: #334155;
    --border-light: #475569;

    --success: #10b981;
    --error: #ef4444;
    --warning: #f59e0b;

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

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 200ms ease;
    --transition-slow: 300ms ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

a {
    color: var(--primary-light);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--primary);
}

/* ============================
   Navigation
   ============================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-md) var(--spacing-xl);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-lg);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text-primary);
}

.logo-icon {
    font-size: 1.5rem;
}

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

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

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

.nav-auth,
.nav-user {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.user-email {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ============================
   Buttons
   ============================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-family: inherit;
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    box-shadow: var(--shadow-md), 0 0 20px rgba(99, 102, 241, 0.2);
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg), 0 0 30px rgba(99, 102, 241, 0.3);
}

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

.btn-outline:hover {
    background: var(--bg-card);
    color: var(--text-primary);
    border-color: var(--border-light);
}

.btn-sm {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: 0.8125rem;
}

.btn-lg {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: 1rem;
}

.btn-block {
    width: 100%;
}

.btn-success {
    background: linear-gradient(135deg, var(--success), #059669);
    color: white;
}

.btn-unlock {
    background: linear-gradient(135deg, var(--accent), #d97706);
    color: white;
}

/* ============================
   Hero Section
   ============================ */
.hero {
    padding: 8rem var(--spacing-xl) 4rem;
    text-align: center;
    background: linear-gradient(180deg, var(--bg-dark) 0%, #1a1a2e 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    height: 100%;
    background: radial-gradient(ellipse at center top, rgba(99, 102, 241, 0.15) 0%, transparent 60%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--primary-light) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-2xl);
}

.search-hero {
    display: flex;
    gap: var(--spacing-md);
    max-width: 700px;
    margin: 0 auto;
    padding: var(--spacing-sm);
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border);
    box-shadow: var(--shadow-xl);
}

.search-input-hero {
    flex: 1;
    padding: var(--spacing-md) var(--spacing-lg);
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 1rem;
    outline: none;
}

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

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--spacing-2xl);
    margin-top: var(--spacing-2xl);
    position: relative;
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-value {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-light);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* ============================
   Main Content
   ============================ */
.main-content {
    padding: var(--spacing-2xl) var(--spacing-xl);
}

.content-container {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: var(--spacing-xl);
}

/* Filters Sidebar */
.filters-sidebar {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    height: fit-content;
    position: sticky;
    top: 100px;
    border: 1px solid var(--border);
}

.filters-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--border);
}

.filter-group {
    margin-bottom: var(--spacing-lg);
}

.filter-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.filter-select,
.filter-input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 0.875rem;
    outline: none;
    transition: border-color var(--transition-fast);
}

.filter-select:focus,
.filter-input:focus {
    border-color: var(--primary);
}

/* Results Section */
.results-section {
    min-height: 500px;
}

.results-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--spacing-lg);
}

.results-title {
    font-size: 1.5rem;
    font-weight: 600;
}

.results-count {
    color: var(--text-muted);
    font-size: 0.875rem;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

/* Professor Card */
.professor-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    transition: all var(--transition-normal);
}

.professor-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: var(--shadow-glow);
}

.professor-name {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.professor-institute {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    background: rgba(99, 102, 241, 0.1);
    color: var(--primary-light);
    font-size: 0.75rem;
    font-weight: 500;
    border-radius: var(--radius-full);
    margin-bottom: var(--spacing-sm);
}

.professor-department {
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: var(--spacing-sm);
}

.professor-research {
    color: var(--text-muted);
    font-size: 0.8125rem;
    line-height: 1.5;
    margin-bottom: var(--spacing-md);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.professor-email-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border);
}

.masked-email {
    font-family: 'Courier New', monospace;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.email-unlocked {
    color: var(--success);
    font-weight: 500;
}

/* Pagination */
.pagination {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-2xl);
}

.pagination-btn {
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.pagination-btn:hover:not(:disabled) {
    background: var(--bg-card-hover);
    color: var(--text-primary);
}

.pagination-btn.active {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

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

/* ============================
   Modals
   ============================ */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 2000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-lg);
}

.modal.hidden {
    display: none;
}

.modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
}

.modal-content {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    width: 100%;
    max-width: 400px;
    max-height: 90vh;
    overflow-y: auto;
    animation: modalIn 0.2s ease;
}

.modal-lg {
    max-width: 700px;
}

@keyframes modalIn {
    from {
        opacity: 0;
        transform: scale(0.95) translateY(10px);
    }

    to {
        opacity: 1;
        transform: scale(1) translateY(0);
    }
}

.modal-close {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-input);
    border: none;
    border-radius: var(--radius-full);
    color: var(--text-muted);
    font-size: 1.25rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--bg-card-hover);
    color: var(--text-primary);
}

.modal-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.modal-subtitle {
    color: var(--text-muted);
    margin-bottom: var(--spacing-lg);
}

/* Forms */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-group label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.form-group input {
    width: 100%;
    padding: var(--spacing-md);
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    outline: none;
    transition: border-color var(--transition-fast);
}

.form-group input:focus {
    border-color: var(--primary);
}

.form-footer {
    text-align: center;
    margin-top: var(--spacing-lg);
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* AI Results */
.ai-results {
    max-height: 400px;
    overflow-y: auto;
}

.ai-result-item {
    padding: var(--spacing-md);
    background: var(--bg-input);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-md);
    border: 1px solid var(--border);
}

.ai-result-item:hover {
    border-color: var(--border-light);
}

/* Unlock Content */
.unlock-professor-name {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.unlock-professor-info {
    color: var(--text-muted);
    margin-bottom: var(--spacing-lg);
}

.unlock-price {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg);
    background: rgba(99, 102, 241, 0.1);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-lg);
}

.price-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-light);
}

.price-label {
    color: var(--text-muted);
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    bottom: var(--spacing-xl);
    right: var(--spacing-xl);
    z-index: 3000;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.toast {
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    animation: toastIn 0.3s ease;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.toast-success {
    border-left: 4px solid var(--success);
}

.toast-error {
    border-left: 4px solid var(--error);
}

@keyframes toastIn {
    from {
        opacity: 0;
        transform: translateX(20px);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* Utilities */
.hidden {
    display: none !important;
}

/* Loading State */
.loading {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-2xl);
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* Responsive */
@media (max-width: 1024px) {
    .content-container {
        grid-template-columns: 1fr;
    }

    .filters-sidebar {
        position: static;
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: var(--spacing-md);
    }

    .filters-title {
        grid-column: 1 / -1;
    }
}

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

    .hero {
        padding: 6rem var(--spacing-md) 3rem;
    }

    .search-hero {
        flex-direction: column;
    }

    .hero-stats {
        gap: var(--spacing-lg);
    }

    .stat-value {
        font-size: 1.75rem;
    }

    .main-content {
        padding: var(--spacing-lg) var(--spacing-md);
    }

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

/* ============================
   Google Sign-In Button
   ============================ */
.google-signin-container {
    text-align: center;
    margin: var(--spacing-xl) 0;
}

.btn-google {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-md);
    width: 100%;
    padding: var(--spacing-md) var(--spacing-xl);
    background: white;
    color: #333;
    font-family: inherit;
    font-size: 1rem;
    font-weight: 500;
    border: 1px solid #dadce0;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.btn-google:hover {
    background: #f7f8f8;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.google-icon {
    flex-shrink: 0;
}

.google-hint {
    margin-top: var(--spacing-md);
    font-size: 0.8125rem;
    color: var(--text-muted);
}

/* Admin Login Toggle */
.admin-login-toggle {
    text-align: center;
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border);
}

.admin-link {
    font-size: 0.75rem;
    color: var(--text-muted);
    opacity: 0.6;
}

.admin-link:hover {
    opacity: 1;
}

.admin-login-form {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--bg-input);
    border-radius: var(--radius-md);
}

/* Signup Benefits */
.signup-benefits {
    margin: var(--spacing-xl) 0;
    padding: var(--spacing-lg);
    background: rgba(16, 185, 129, 0.1);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(16, 185, 129, 0.2);
}

.signup-benefits h4 {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--success);
    margin-bottom: var(--spacing-sm);
}

.signup-benefits ul {
    list-style: none;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.signup-benefits li {
    padding: var(--spacing-xs) 0;
}

/* User Credits Display */
.user-credits {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-xs) var(--spacing-sm);
    background: rgba(16, 185, 129, 0.1);
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    color: var(--success);
}

/* ============================
   Contact Section
   ============================ */
.contact-section {
    padding: var(--spacing-3xl) var(--spacing-xl);
    background: linear-gradient(180deg, var(--bg-primary) 0%, rgba(99, 102, 241, 0.03) 100%);
    border-top: 1px solid var(--border);
}

.contact-container {
    max-width: 1000px;
    margin: 0 auto;
    text-align: center;
}

.contact-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--primary-light), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.contact-subtitle {
    color: var(--text-muted);
    font-size: 1.1rem;
    margin-bottom: var(--spacing-xl);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.feature-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    transition: all var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: 0 12px 40px rgba(99, 102, 241, 0.15);
}

.feature-icon {
    display: block;
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
}

.feature-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.feature-card p {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.contact-form-container {
    max-width: 500px;
    margin: 0 auto;
    padding: var(--spacing-2xl);
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    text-align: left;
}

.contact-form-container h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    text-align: center;
}

.contact-form-container .form-group {
    margin-bottom: var(--spacing-md);
}

.contact-form-container label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
}

.contact-form-container .form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
    transition: all var(--transition-fast);
}

.contact-form-container .form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.contact-form-container textarea.form-control {
    resize: vertical;
    min-height: 100px;
}

.contact-form-container select.form-control {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%239ca3af' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem center;
    padding-right: 2.5rem;
}

/* ============================
   Footer
   ============================ */
.site-footer {
    padding: var(--spacing-2xl) var(--spacing-xl);
    background: var(--bg-card);
    border-top: 1px solid var(--border);
}

.footer-container {
    max-width: 1000px;
    margin: 0 auto;
    text-align: center;
}

.footer-brand {
    margin-bottom: var(--spacing-lg);
}

.footer-logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.footer-tagline {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-top: var(--spacing-xs);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border);
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--primary-light);
}

.footer-bottom {
    padding-top: var(--spacing-sm);
}

.footer-credit {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    font-style: italic;
}

.footer-copyright {
    font-size: 0.75rem;
    color: var(--text-muted);
}