/* ============== VARIABLES ============== */
:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: rgba(255, 255, 255, 0.03);
    --bg-card-hover: rgba(255, 255, 255, 0.06);
    --text-primary: #ffffff;
    --text-secondary: #a0a0b0;
    --text-muted: #606070;
    --accent: #6366f1;
    --accent-hover: #818cf8;
    --accent-light: rgba(99, 102, 241, 0.1);
    --success: #10b981;
    --warning: #f59e0b;
    --error: #ef4444;
    --border: rgba(255, 255, 255, 0.08);
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    --radius: 12px;
    --radius-sm: 8px;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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

a {
    color: var(--accent);
    text-decoration: none;
    transition: color 0.2s;
}

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

/* ============== AUTH PAGES ============== */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    background:
        radial-gradient(circle at 20% 20%, rgba(99, 102, 241, 0.15) 0%, transparent 40%),
        radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.1) 0%, transparent 40%),
        var(--bg-primary);
}

.auth-card {
    width: 100%;
    max-width: 420px;
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2.5rem;
    box-shadow: var(--shadow);
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.auth-header .logo {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.auth-header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.auth-header p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.auth-footer {
    text-align: center;
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* ============== TABS ============== */
.tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    background: var(--bg-secondary);
    padding: 4px;
    border-radius: var(--radius-sm);
}

.tab {
    flex: 1;
    padding: 0.75rem 1rem;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    border-radius: 6px;
    transition: all 0.2s;
}

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

.tab.active {
    background: var(--accent);
    color: white;
}

/* ============== FORMS ============== */
.auth-form {
    display: none;
}

.auth-form.active {
    display: block;
}

.form-group {
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 0.875rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-light);
}

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

.form-group small {
    display: block;
    margin-top: 0.5rem;
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* ============== BUTTONS ============== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.875rem 1.5rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-primary {
    width: 100%;
    background: var(--accent);
    color: white;
}

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
}

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

.btn-secondary:hover {
    background: var(--bg-card-hover);
}

.btn-outline {
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border);
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
}

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

.btn-success {
    background: var(--success);
    color: white;
}

.btn-danger {
    background: var(--error);
    color: white;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
}

/* ============== MESSAGES ============== */
.error-message {
    margin-top: 1rem;
    padding: 0.75rem 1rem;
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: var(--radius-sm);
    color: var(--error);
    font-size: 0.9rem;
    display: none;
}

.error-message.show {
    display: block;
}

.success-message {
    margin-top: 1rem;
    padding: 0.75rem 1rem;
    background: rgba(16, 185, 129, 0.1);
    border: 1px solid rgba(16, 185, 129, 0.3);
    border-radius: var(--radius-sm);
    color: var(--success);
    font-size: 0.9rem;
    display: none;
}

.success-message.show {
    display: block;
}

/* ============== NAVBAR ============== */
.navbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 2rem;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar.admin-nav {
    background: linear-gradient(90deg, var(--bg-secondary), rgba(99, 102, 241, 0.1));
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.25rem;
    font-weight: 600;
}

.nav-brand .logo {
    font-size: 1.5rem;
}

.nav-brand .badge {
    background: var(--accent);
    color: white;
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
}

.nav-links {
    display: flex;
    gap: 0.5rem;
}

.nav-links a {
    padding: 0.5rem 1rem;
    color: var(--text-secondary);
    border-radius: var(--radius-sm);
    transition: all 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text-primary);
    background: var(--bg-card);
}

.nav-user {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.nav-user span {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ============== CONTAINER ============== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.page-title {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 2rem;
}

/* ============== CARDS ============== */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.card h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border);
}

/* ============== STATS ============== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-icon {
    font-size: 2rem;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--accent-light);
    border-radius: var(--radius-sm);
}

.stat-content h3 {
    font-size: 1.5rem;
    font-weight: 700;
}

.stat-content p {
    color: var(--text-secondary);
    font-size: 0.85rem;
}

/* ============== PROFESSORS ============== */
.search-box {
    margin-bottom: 1.5rem;
}

.search-box input {
    width: 100%;
    padding: 1rem 1.25rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text-primary);
    font-size: 1rem;
}

.search-box input:focus {
    outline: none;
    border-color: var(--accent);
}

.professors-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1rem;
}

.professor-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.25rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    transition: all 0.2s;
}

.professor-card:hover {
    background: var(--bg-card-hover);
    border-color: var(--accent);
}

.professor-card.following {
    border-color: var(--success);
    background: rgba(16, 185, 129, 0.05);
}

.professor-avatar {
    width: 50px;
    height: 50px;
    background: var(--accent-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    color: var(--accent);
    font-weight: 600;
}

.professor-info {
    flex: 1;
}

.professor-info h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.professor-info p {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.professor-card .btn {
    padding: 0.5rem 1rem;
}

.professors-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.empty-state {
    color: var(--text-muted);
    text-align: center;
    padding: 2rem;
}

/* ============== INFO ROWS ============== */
.info-row {
    display: flex;
    justify-content: space-between;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border);
}

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

.info-row span:first-child {
    color: var(--text-secondary);
}

/* ============== USERS TABLE ============== */
.users-table {
    margin-top: 1rem;
}

.user-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-sm);
    margin-bottom: 0.5rem;
}

.user-info {
    flex: 1;
}

.user-info h4 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.user-info p {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.user-status {
    display: flex;
    gap: 0.5rem;
    margin-right: 1rem;
}

.status-badge {
    padding: 0.25rem 0.5rem;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 500;
}

.status-badge.pending {
    background: rgba(245, 158, 11, 0.2);
    color: var(--warning);
}

.status-badge.approved {
    background: rgba(16, 185, 129, 0.2);
    color: var(--success);
}

.status-badge.admin {
    background: rgba(99, 102, 241, 0.2);
    color: var(--accent);
}

.user-actions {
    display: flex;
    gap: 0.5rem;
}

/* ============== RESPONSIVE ============== */
@media (max-width: 768px) {
    .navbar {
        flex-wrap: wrap;
        gap: 1rem;
        padding: 1rem;
    }

    .nav-links {
        order: 3;
        width: 100%;
        justify-content: center;
    }

    .container {
        padding: 1rem;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .user-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .user-actions {
        width: 100%;
        justify-content: flex-end;
    }
}

/* ============== CODE ============== */
code {
    background: var(--bg-secondary);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-family: 'Menlo', 'Monaco', monospace;
    font-size: 0.9em;
}