/* ========================================
   Unit Detail Pages Styles
   ======================================== */

.unit-page {
    min-height: 100vh;
    background: var(--dark);
    padding-top: 80px;
}

/* Unit Hero */
.unit-hero {
    position: relative;
    padding: 60px 0 80px;
    overflow: hidden;
}

.unit-hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 0;
}

.unit-hero[data-phase="foundation"]::before { background: radial-gradient(ellipse at 50% 0%, rgba(99,102,241,0.15) 0%, transparent 60%); }
.unit-hero[data-phase="intermediate"]::before { background: radial-gradient(ellipse at 50% 0%, rgba(6,182,212,0.15) 0%, transparent 60%); }
.unit-hero[data-phase="advanced"]::before { background: radial-gradient(ellipse at 50% 0%, rgba(245,158,11,0.15) 0%, transparent 60%); }
.unit-hero[data-phase="mastery"]::before { background: radial-gradient(ellipse at 50% 0%, rgba(239,68,68,0.15) 0%, transparent 60%); }

.unit-hero .container {
    position: relative;
    z-index: 1;
}

.unit-breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 24px;
    font-size: 0.9rem;
}

.unit-breadcrumb a {
    color: var(--gray);
    text-decoration: none;
    transition: var(--transition);
}

.unit-breadcrumb a:hover { color: var(--primary-light); }
.unit-breadcrumb .sep { color: var(--dark-3); }
.unit-breadcrumb .current { color: var(--primary-light); }

.unit-hero-grid {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 40px;
    align-items: start;
}

.unit-hero-info .unit-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    border-radius: 50px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 16px;
}

.unit-hero[data-phase="foundation"] .unit-badge { background: rgba(99,102,241,0.15); color: var(--primary-light); }
.unit-hero[data-phase="intermediate"] .unit-badge { background: rgba(6,182,212,0.15); color: var(--secondary); }
.unit-hero[data-phase="advanced"] .unit-badge { background: rgba(245,158,11,0.15); color: var(--accent); }
.unit-hero[data-phase="mastery"] .unit-badge { background: rgba(239,68,68,0.15); color: var(--danger); }

.unit-hero-info h1 {
    font-size: 2.4rem;
    font-weight: 900;
    color: var(--white);
    margin-bottom: 16px;
    line-height: 1.3;
}

.unit-hero-info .unit-desc {
    font-size: 1.1rem;
    color: var(--gray-light);
    margin-bottom: 24px;
    max-width: 650px;
    line-height: 1.8;
}

.unit-meta {
    display: flex;
    gap: 24px;
    flex-wrap: wrap;
}

.unit-meta-item {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--gray);
    font-size: 0.9rem;
}

.unit-meta-item i {
    color: var(--primary-light);
}

.unit-hero-number {
    font-size: 8rem;
    font-weight: 900;
    line-height: 1;
    opacity: 0.15;
}

.unit-hero[data-phase="foundation"] .unit-hero-number { color: var(--primary); }
.unit-hero[data-phase="intermediate"] .unit-hero-number { color: var(--secondary); }
.unit-hero[data-phase="advanced"] .unit-hero-number { color: var(--accent); }
.unit-hero[data-phase="mastery"] .unit-hero-number { color: var(--danger); }

/* Sidebar Layout */
.unit-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 40px;
    padding: 0 0 80px;
}

/* Sidebar */
.unit-sidebar {
    position: sticky;
    top: 80px;
    max-height: calc(100vh - 100px);
    overflow-y: auto;
    padding-left: 20px;
    border-left: 1px solid rgba(99,102,241,0.1);
}

.unit-sidebar::-webkit-scrollbar { width: 3px; }
.unit-sidebar::-webkit-scrollbar-track { background: transparent; }
.unit-sidebar::-webkit-scrollbar-thumb { background: var(--dark-3); border-radius: 3px; }

.sidebar-title {
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--gray);
    margin-bottom: 16px;
    font-weight: 600;
}

.sidebar-nav {
    list-style: none;
    margin-bottom: 32px;
}

.sidebar-nav li a {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    color: var(--gray-light);
    text-decoration: none;
    font-size: 0.88rem;
    transition: var(--transition);
    border-right: 3px solid transparent;
}

.sidebar-nav li a:hover,
.sidebar-nav li a.active {
    color: var(--white);
    background: rgba(99,102,241,0.08);
    border-right-color: var(--primary);
}

.sidebar-nav li a i {
    width: 18px;
    font-size: 0.8rem;
    color: var(--primary-light);
}

.sidebar-units {
    list-style: none;
}

.sidebar-units li a {
    display: block;
    padding: 8px 14px;
    border-radius: var(--radius-sm);
    color: var(--gray);
    text-decoration: none;
    font-size: 0.82rem;
    transition: var(--transition);
    border-right: 2px solid transparent;
}

.sidebar-units li a:hover { color: var(--primary-light); border-right-color: var(--primary); }
.sidebar-units li a.current { color: var(--white); background: rgba(99,102,241,0.1); border-right-color: var(--primary); font-weight: 600; }

/* Unit Content */
.unit-main-content {
    min-width: 0;
}

.content-block {
    margin-bottom: 48px;
    scroll-margin-top: 100px;
}

.content-block h2 {
    font-size: 1.6rem;
    font-weight: 800;
    color: var(--white);
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.content-block h2 i {
    color: var(--primary-light);
    font-size: 1.2rem;
}

.content-block h3 {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--white);
    margin: 20px 0 12px;
}

.content-block p {
    color: var(--gray-light);
    line-height: 1.9;
    font-size: 0.95rem;
    margin-bottom: 12px;
}

/* Concept Cards */
.concept-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 16px;
    margin: 20px 0;
}

.concept-card {
    background: rgba(30,41,59,0.5);
    border: 1px solid rgba(99,102,241,0.1);
    border-radius: var(--radius-md);
    padding: 24px;
    transition: var(--transition);
}

.concept-card:hover {
    transform: translateY(-3px);
    border-color: rgba(99,102,241,0.25);
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.concept-card h4 {
    color: var(--white);
    font-size: 1rem;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.concept-card h4 .en {
    font-size: 0.8rem;
    color: var(--primary-light);
    font-weight: 400;
}

.concept-card p {
    color: var(--gray);
    font-size: 0.88rem;
    line-height: 1.7;
}

/* Info Box */
.info-box {
    background: rgba(99,102,241,0.08);
    border-right: 4px solid var(--primary);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    padding: 20px 24px;
    margin: 20px 0;
}

.info-box.warning {
    background: rgba(245,158,11,0.08);
    border-right-color: var(--accent);
}

.info-box.success {
    background: rgba(16,185,129,0.08);
    border-right-color: var(--success);
}

.info-box h4 {
    color: var(--white);
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.info-box p {
    color: var(--gray-light);
    font-size: 0.9rem;
    margin-bottom: 0;
}

/* Objectives List */
.objectives-list {
    list-style: none;
    display: grid;
    gap: 12px;
    margin: 16px 0;
}

.objectives-list li {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 14px 18px;
    background: rgba(30,41,59,0.4);
    border-radius: var(--radius-sm);
    color: var(--gray-light);
    font-size: 0.92rem;
    transition: var(--transition);
}

.objectives-list li:hover {
    background: rgba(30,41,59,0.7);
}

.objectives-list li .obj-icon {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: rgba(99,102,241,0.15);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    color: var(--primary-light);
    font-size: 0.75rem;
    font-weight: 700;
}

/* Steps / Process */
.process-steps {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin: 20px 0;
}

.step-item {
    display: flex;
    gap: 16px;
    padding: 20px;
    background: rgba(30,41,59,0.4);
    border-radius: var(--radius-md);
    border: 1px solid rgba(99,102,241,0.08);
    transition: var(--transition);
}

.step-item:hover {
    border-color: rgba(99,102,241,0.2);
    background: rgba(30,41,59,0.6);
}

.step-num {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--gradient-1);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
    font-weight: 800;
    font-size: 1rem;
    flex-shrink: 0;
}

.step-content h4 {
    color: var(--white);
    margin-bottom: 4px;
}

.step-content p {
    color: var(--gray);
    font-size: 0.88rem;
    margin-bottom: 0;
}

/* Comparison Table */
.comparison-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    border-radius: var(--radius-md);
    overflow: hidden;
    margin: 20px 0;
}

.comparison-table th {
    background: rgba(99,102,241,0.15);
    color: var(--white);
    padding: 14px 18px;
    font-size: 0.9rem;
    font-weight: 700;
    text-align: right;
}

.comparison-table td {
    background: rgba(30,41,59,0.4);
    color: var(--gray-light);
    padding: 12px 18px;
    font-size: 0.88rem;
    border-bottom: 1px solid rgba(255,255,255,0.03);
}

.comparison-table tr:hover td {
    background: rgba(30,41,59,0.7);
}

/* Practical Exercise */
.exercise-box {
    background: linear-gradient(135deg, rgba(99,102,241,0.1), rgba(6,182,212,0.1));
    border: 1px solid rgba(99,102,241,0.2);
    border-radius: var(--radius-lg);
    padding: 32px;
    margin: 24px 0;
}

.exercise-box h3 {
    color: var(--white);
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 16px;
}

.exercise-box h3 i { color: var(--accent); }

.exercise-box .exercise-steps {
    list-style: none;
    counter-reset: exercise;
}

.exercise-box .exercise-steps li {
    counter-increment: exercise;
    padding: 8px 0;
    color: var(--gray-light);
    font-size: 0.92rem;
    padding-right: 32px;
    position: relative;
}

.exercise-box .exercise-steps li::before {
    content: counter(exercise);
    position: absolute;
    right: 0;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: rgba(99,102,241,0.2);
    color: var(--primary-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    font-weight: 700;
}

/* Mini Mind Map */
.unit-mindmap {
    background: rgba(15,23,42,0.6);
    border: 1px solid rgba(99,102,241,0.1);
    border-radius: var(--radius-lg);
    padding: 32px;
    margin: 24px 0;
    text-align: center;
}

.unit-mindmap h3 {
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.mini-map {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 12px;
    position: relative;
}

.mini-map-center {
    padding: 14px 24px;
    border-radius: var(--radius-md);
    background: var(--gradient-1);
    color: var(--white);
    font-weight: 700;
    font-size: 0.95rem;
    width: 100%;
    max-width: 300px;
    margin-bottom: 8px;
}

.mini-map-node {
    padding: 10px 18px;
    border-radius: var(--radius-sm);
    background: rgba(30,41,59,0.6);
    border: 1px solid rgba(99,102,241,0.15);
    color: var(--gray-light);
    font-size: 0.85rem;
    transition: var(--transition);
    cursor: default;
}

.mini-map-node:hover {
    border-color: rgba(99,102,241,0.4);
    color: var(--white);
    transform: translateY(-2px);
}

/* Navigation between units */
.unit-nav {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    padding-top: 40px;
    border-top: 1px solid rgba(255,255,255,0.05);
    margin-top: 40px;
}

.unit-nav-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 24px;
    border-radius: var(--radius-md);
    background: rgba(30,41,59,0.5);
    border: 1px solid rgba(99,102,241,0.1);
    color: var(--gray-light);
    text-decoration: none;
    transition: var(--transition);
    max-width: 48%;
}

.unit-nav-btn:hover {
    background: rgba(99,102,241,0.1);
    border-color: rgba(99,102,241,0.3);
    color: var(--white);
}

.unit-nav-btn .nav-label {
    font-size: 0.75rem;
    color: var(--gray);
    display: block;
}

.unit-nav-btn .nav-title {
    font-size: 0.9rem;
    font-weight: 600;
    display: block;
}

/* Responsive */
@media (max-width: 1024px) {
    .unit-layout {
        grid-template-columns: 1fr;
    }
    .unit-sidebar {
        position: static;
        max-height: none;
        border-left: none;
        padding-left: 0;
        display: flex;
        flex-wrap: wrap;
        gap: 8px;
        margin-bottom: 20px;
        padding-bottom: 20px;
        border-bottom: 1px solid rgba(99,102,241,0.1);
    }
    .sidebar-title { width: 100%; }
    .sidebar-nav { display: flex; flex-wrap: wrap; gap: 4px; margin-bottom: 0; }
    .sidebar-nav li a { padding: 8px 12px; font-size: 0.8rem; border-right: none; border-bottom: 2px solid transparent; }
    .sidebar-nav li a:hover, .sidebar-nav li a.active { border-right: none; border-bottom-color: var(--primary); }
    .sidebar-units { display: none; }
    .unit-hero-info h1 { font-size: 1.8rem; }
}

@media (max-width: 768px) {
    .unit-hero-grid {
        grid-template-columns: 1fr;
    }
    .unit-hero-number { display: none; }
    .unit-hero-info h1 { font-size: 1.6rem; }
    .unit-nav { flex-direction: column; }
    .unit-nav-btn { max-width: 100%; }
    .concept-grid { grid-template-columns: 1fr; }
}

/* ========================================
   Light Theme — Unit Page
   ======================================== */
body.light-theme .unit-hero {
    background: linear-gradient(135deg, rgba(99,102,241,0.06) 0%, rgba(6,182,212,0.04) 100%);
}

body.light-theme .unit-hero h1 {
    color: #0f172a;
}

body.light-theme .unit-hero .unit-desc {
    color: #475569;
}

body.light-theme .unit-badge {
    background: rgba(99, 102, 241, 0.08);
    color: #4f46e5;
}

body.light-theme .unit-breadcrumb a {
    color: #64748b;
}

body.light-theme .unit-sidebar {
    background: rgba(255, 255, 255, 0.9);
    border-color: rgba(99, 102, 241, 0.1);
}

body.light-theme .sidebar-title {
    color: #0f172a;
}

body.light-theme .sidebar-nav li a {
    color: #475569;
}

body.light-theme .sidebar-nav li a:hover,
body.light-theme .sidebar-nav li a.active {
    color: #6366f1;
    background: rgba(99, 102, 241, 0.06);
}

body.light-theme .sidebar-units a {
    color: #64748b;
}

body.light-theme .sidebar-units a.current {
    color: #6366f1;
}

body.light-theme .content-block {
    background: rgba(255, 255, 255, 0.85);
    border-color: rgba(99, 102, 241, 0.08);
}

body.light-theme .content-block h2 {
    color: #0f172a;
}

body.light-theme .concept-card {
    background: rgba(241, 245, 249, 0.8);
    border-color: rgba(99, 102, 241, 0.1);
}

body.light-theme .concept-card h4 {
    color: #0f172a;
}

body.light-theme .concept-card p {
    color: #475569;
}

body.light-theme .unit-nav-btn {
    background: rgba(255, 255, 255, 0.85);
    border-color: rgba(99, 102, 241, 0.1);
    color: #334155;
}

body.light-theme .unit-nav-btn:hover {
    border-color: rgba(99, 102, 241, 0.3);
}

body.light-theme .objectives-list li {
    color: #334155;
}

body.light-theme .exercise-box,
body.light-theme .comparison-table {
    background: rgba(255, 255, 255, 0.85);
    border-color: rgba(99, 102, 241, 0.1);
}

body.light-theme .comparison-table th {
    background: rgba(99, 102, 241, 0.06);
    color: #0f172a;
}

body.light-theme .comparison-table td {
    border-color: rgba(99, 102, 241, 0.08);
    color: #334155;
}

body.light-theme .process-step {
    background: rgba(255, 255, 255, 0.85);
    border-color: rgba(99, 102, 241, 0.1);
}

body.light-theme .takeaway-item {
    background: rgba(241, 245, 249, 0.8);
    color: #334155;
}