/* =============================================================================
   amorphic learn — clean, focused, Inter font
   ============================================================================= */

:root {
    --bg: #fafafa;
    --card: #ffffff;
    --border: #e8e8e8;
    --text: #1a1a1a;
    --text-muted: #6b7280;
    --primary: #111111;
    --primary-hover: #333333;
    --accent: #2563eb;
    --success: #10b981;
    --error: #ef4444;
    --radius: 12px;
    --radius-sm: 8px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* Nav */
.navbar {
    background: var(--primary);
    color: white;
    padding: 0 2rem;
    height: 56px;
    display: flex;
    align-items: center;
}
.nav-container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.nav-brand {
    color: white;
    text-decoration: none;
    font-size: 1.1rem;
    letter-spacing: -0.02em;
}
.brand-sub {
    font-weight: 300;
    opacity: 0.7;
    margin-left: 0.3rem;
}
.nav-right {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}
.nav-user { font-size: 0.85rem; opacity: 0.8; }
.nav-link {
    color: white;
    text-decoration: none;
    font-size: 0.85rem;
    opacity: 0.7;
    transition: opacity 0.2s;
}
.nav-link:hover { opacity: 1; }

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

/* Auth */
.auth-body {
    background: var(--primary);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
}
.auth-container {
    width: 100%;
    max-width: 400px;
    padding: 2rem;
}
.auth-card {
    background: white;
    padding: 2.5rem;
    border-radius: var(--radius);
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
}
.auth-brand {
    font-size: 1.5rem;
    text-align: center;
    margin-bottom: 0.25rem;
    letter-spacing: -0.02em;
}
.auth-subtitle {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 2rem;
}

/* Forms */
.form-group {
    margin-bottom: 1.25rem;
}
.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 500;
    margin-bottom: 0.4rem;
    color: var(--text);
}
input, select, textarea {
    width: 100%;
    padding: 0.7rem 0.9rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 0.9rem;
    transition: border-color 0.2s;
}
input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--primary);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.65rem 1.5rem;
    border: none;
    border-radius: var(--radius-sm);
    font-family: inherit;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.2s;
}
.btn-primary {
    background: var(--primary);
    color: white;
}
.btn-primary:hover { background: var(--primary-hover); }
.btn-secondary {
    background: var(--bg);
    color: var(--text);
    border: 1px solid var(--border);
}
.btn-secondary:hover { background: var(--border); }
.btn-full { width: 100%; text-align: center; }

/* Alerts */
.alert { padding: 0.75rem 1rem; border-radius: var(--radius-sm); margin-bottom: 1.5rem; font-size: 0.9rem; }
.alert-error { background: #fef2f2; color: var(--error); border: 1px solid #fecaca; }

/* Dashboard */
.welcome { margin-bottom: 2rem; }
.welcome h1 { font-size: 1.8rem; font-weight: 700; letter-spacing: -0.03em; }
.welcome p { color: var(--text-muted); margin-top: 0.25rem; }

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}
.course-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    text-decoration: none;
    color: inherit;
    transition: box-shadow 0.2s, transform 0.2s;
}
.course-card:hover {
    box-shadow: 0 8px 30px rgba(0,0,0,0.08);
    transform: translateY(-2px);
}
.course-thumb {
    height: 160px;
    background: linear-gradient(135deg, #1a1a1a, #333);
    background-size: cover;
    background-position: center;
    display: flex;
    align-items: center;
    justify-content: center;
}
.course-thumb-placeholder { font-size: 3rem; }
.course-info { padding: 1.25rem; }
.course-info h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 0.4rem; letter-spacing: -0.02em; }
.course-info p { font-size: 0.85rem; color: var(--text-muted); margin-bottom: 1rem; }
.course-meta { display: flex; align-items: center; gap: 0.75rem; }
.lesson-count { font-size: 0.8rem; color: var(--text-muted); white-space: nowrap; }
.progress-bar { flex: 1; height: 4px; background: var(--border); border-radius: 2px; overflow: hidden; }
.progress-fill { height: 100%; background: var(--success); border-radius: 2px; transition: width 0.3s; }
.progress-text { font-size: 0.8rem; color: var(--text-muted); white-space: nowrap; }

/* Course Page */
.course-header { margin-bottom: 2rem; }
.course-header h1 { font-size: 1.8rem; font-weight: 700; letter-spacing: -0.03em; margin: 0.5rem 0; }
.course-desc { color: var(--text-muted); margin-bottom: 1rem; }
.back-link { color: var(--text-muted); text-decoration: none; font-size: 0.85rem; }
.back-link:hover { color: var(--text); }

.progress-bar-lg { height: 8px; background: var(--border); border-radius: 4px; overflow: hidden; margin-bottom: 0.5rem; }
.course-progress-bar span { font-size: 0.85rem; color: var(--text-muted); }

.lesson-list { display: flex; flex-direction: column; gap: 0.5rem; }
.lesson-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: inherit;
    transition: border-color 0.2s;
}
.lesson-item:hover { border-color: var(--primary); }
.lesson-item.completed { opacity: 0.7; }
.lesson-number {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--bg);
    font-weight: 600;
    font-size: 0.85rem;
    flex-shrink: 0;
}
.lesson-item.completed .lesson-number { background: var(--success); color: white; }
.check { font-size: 1rem; }
.lesson-info { flex: 1; }
.lesson-info h3 { font-size: 0.95rem; font-weight: 500; }
.lesson-info p { font-size: 0.8rem; color: var(--text-muted); margin-top: 0.15rem; }
.lesson-duration { font-size: 0.8rem; color: var(--text-muted); }

/* Lesson Page */
.lesson-page {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 2rem;
    min-height: calc(100vh - 56px - 4rem);
}
.lesson-sidebar {
    border-right: 1px solid var(--border);
    padding-right: 1.5rem;
}
.sidebar-lessons {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    margin-top: 1rem;
}
.sidebar-item {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--text-muted);
    font-size: 0.85rem;
    transition: background 0.2s;
}
.sidebar-item:hover { background: var(--bg); }
.sidebar-item.active { background: var(--bg); color: var(--text); font-weight: 500; }
.sidebar-item.completed .sidebar-num { color: var(--success); }
.sidebar-num { width: 1.5rem; text-align: center; font-size: 0.8rem; flex-shrink: 0; }
.sidebar-title { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.lesson-content h1 {
    font-size: 1.6rem;
    font-weight: 700;
    letter-spacing: -0.03em;
    margin-bottom: 1.5rem;
}
.video-container {
    margin-bottom: 1.5rem;
    border-radius: var(--radius);
    overflow: hidden;
    background: black;
}
.video-container video {
    width: 100%;
    display: block;
}
.lesson-text {
    font-size: 0.95rem;
    line-height: 1.8;
    margin-bottom: 2rem;
}
.lesson-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
    margin-top: 2rem;
}
.lesson-arrows { display: flex; gap: 0.75rem; }
.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-size: 0.9rem;
}
.checkbox-label input { width: auto; }

/* Admin */
.admin-page h1 { font-size: 1.8rem; font-weight: 700; margin-bottom: 2rem; }
.admin-grid { display: grid; grid-template-columns: 1fr; gap: 2rem; }
.admin-section {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
}
.admin-section h2 { font-size: 1.2rem; font-weight: 600; margin-bottom: 1rem; }
.admin-section h3 { font-size: 1rem; font-weight: 500; margin: 1.5rem 0 0.75rem; }
.admin-table { width: 100%; border-collapse: collapse; font-size: 0.85rem; }
.admin-table th, .admin-table td { text-align: left; padding: 0.5rem; border-bottom: 1px solid var(--border); }
.admin-table th { font-weight: 600; }
.admin-form { display: flex; flex-direction: column; gap: 0.75rem; }
.admin-form input, .admin-form select, .admin-form textarea { padding: 0.6rem 0.8rem; }

/* Empty State */
.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-muted);
}

/* Error */
.error-page { text-align: center; padding: 4rem 2rem; }
.error-page h1 { font-size: 2rem; margin-bottom: 0.5rem; }
.error-page p { color: var(--text-muted); margin-bottom: 2rem; }

/* Responsive */
@media (max-width: 768px) {
    .lesson-page { grid-template-columns: 1fr; }
    .lesson-sidebar { border-right: none; border-bottom: 1px solid var(--border); padding: 0 0 1rem; }
    .course-grid { grid-template-columns: 1fr; }
    .container { padding: 1rem; }
}