:root {
    --primary: #0f766e;
    --primary-dark: #0d5c56;
    --primary-light: #14b8a6;
    --bg: #f8fafa;
    --bg-card: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --success: #22c55e;
    --danger: #ef4444;
    --warning: #f59e0b;
    --radius: 12px;
    --shadow: 0 2px 8px rgba(0,0,0,0.08);
    --shadow-lg: 0 4px 16px rgba(0,0,0,0.12);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Hiragino Sans', 'Noto Sans JP', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    padding: 0 20px;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-lg);
}

.header-inner {
    max-width: 1000px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 60px;
}

.logo {
    font-size: 1.4rem;
    font-weight: 800;
    letter-spacing: 0.5px;
}

.logo-accent {
    color: #a7f3d0;
    margin-left: 4px;
    font-weight: 600;
}

.menu-btn {
    display: flex;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.menu-btn span {
    display: block;
    width: 24px;
    height: 2px;
    background: #fff;
    border-radius: 2px;
    transition: 0.3s;
}

.mobile-nav {
    background: var(--primary-dark);
    display: none;
    flex-direction: column;
    position: sticky;
    top: 60px;
    z-index: 99;
}

.mobile-nav.active { display: flex; }

.nav-link {
    color: #fff;
    text-decoration: none;
    padding: 14px 24px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    transition: background 0.2s;
}

.nav-link:hover { background: rgba(255,255,255,0.1); }

/* Main */
.main {
    max-width: 1000px;
    margin: 0 auto;
    padding: 24px 16px;
    width: 100%;
    flex: 1;
}

/* Dashboard */
.dashboard-hero {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    padding: 40px 28px;
    border-radius: var(--radius);
    margin-bottom: 28px;
    text-align: center;
}

.dashboard-hero h2 {
    font-size: 1.6rem;
    margin-bottom: 12px;
}

.dashboard-hero p {
    font-size: 0.95rem;
    opacity: 0.9;
    line-height: 1.8;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-bottom: 28px;
}

.stat-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 20px 16px;
    text-align: center;
    box-shadow: var(--shadow);
}

.stat-value {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--primary);
}

.stat-label {
    font-size: 0.78rem;
    color: var(--text-light);
    margin-top: 4px;
}

.progress-overview {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    margin-bottom: 28px;
}

.progress-overview h3 {
    margin-bottom: 16px;
    font-size: 1.05rem;
}

.progress-bar-container {
    background: var(--border);
    border-radius: 20px;
    height: 12px;
    overflow: hidden;
    margin-bottom: 8px;
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--primary-light));
    border-radius: 20px;
    transition: width 0.5s ease;
}

.progress-text {
    font-size: 0.85rem;
    color: var(--text-light);
    text-align: right;
}

/* Level Cards */
.section-title {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 3px solid var(--primary);
    display: inline-block;
}

.level-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 14px;
    margin-top: 16px;
}

.level-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: var(--shadow);
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    border-left: 4px solid var(--primary);
    display: flex;
    align-items: center;
    gap: 16px;
}

.level-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.level-card.completed { border-left-color: var(--success); }
.level-card.locked { opacity: 0.5; cursor: not-allowed; border-left-color: var(--border); }

.level-number {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--primary);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.level-card.completed .level-number { background: var(--success); }
.level-card.locked .level-number { background: var(--border); color: var(--text-light); }

.level-info { flex: 1; }

.level-info h3 {
    font-size: 1rem;
    margin-bottom: 4px;
}

.level-info p {
    font-size: 0.82rem;
    color: var(--text-light);
}

.level-badge {
    font-size: 0.7rem;
    padding: 3px 10px;
    border-radius: 20px;
    font-weight: 600;
    flex-shrink: 0;
}

.badge-completed { background: #dcfce7; color: #16a34a; }
.badge-available { background: #dbeafe; color: #2563eb; }
.badge-locked { background: #f1f5f9; color: #94a3b8; }

/* Module View */
.module-header {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    padding: 28px 24px;
    border-radius: var(--radius);
    margin-bottom: 24px;
}

.module-header h2 { font-size: 1.3rem; margin-bottom: 6px; }
.module-header p { opacity: 0.85; font-size: 0.9rem; }

.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--primary);
    font-weight: 600;
    cursor: pointer;
    margin-bottom: 16px;
    font-size: 0.92rem;
    background: none;
    border: none;
    padding: 0;
}

.back-btn:hover { color: var(--primary-dark); }

.content-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 28px 24px;
    box-shadow: var(--shadow);
    margin-bottom: 20px;
    line-height: 1.9;
    font-size: 0.95rem;
}

.content-card h3 {
    color: var(--primary);
    margin: 24px 0 12px;
    font-size: 1.08rem;
    padding-bottom: 6px;
    border-bottom: 2px solid var(--border);
}

.content-card h3:first-child { margin-top: 0; }

.content-card p { margin-bottom: 14px; }

.content-card ul, .content-card ol {
    margin: 10px 0 14px 20px;
}

.content-card li { margin-bottom: 6px; }

.start-quiz-btn {
    display: block;
    width: 100%;
    padding: 16px;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: #fff;
    border: none;
    border-radius: var(--radius);
    font-size: 1.05rem;
    font-weight: 700;
    cursor: pointer;
    transition: opacity 0.2s;
    text-align: center;
}

.start-quiz-btn:hover { opacity: 0.9; }

/* Quiz */
.quiz-container {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 28px 24px;
    box-shadow: var(--shadow);
}

.quiz-progress {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 24px;
    font-size: 0.85rem;
    color: var(--text-light);
}

.quiz-progress-bar {
    flex: 1;
    height: 6px;
    background: var(--border);
    border-radius: 6px;
    overflow: hidden;
}

.quiz-progress-fill {
    height: 100%;
    background: var(--primary);
    border-radius: 6px;
    transition: width 0.3s;
}

.quiz-question {
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 20px;
    line-height: 1.7;
}

.quiz-choices {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 20px;
}

.quiz-choice {
    padding: 14px 18px;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
    transition: all 0.2s;
    font-size: 0.93rem;
    background: var(--bg-card);
    text-align: left;
    width: 100%;
}

.quiz-choice:hover { border-color: var(--primary); background: #f0fdfa; }
.quiz-choice.selected { border-color: var(--primary); background: #f0fdfa; font-weight: 600; }
.quiz-choice.correct { border-color: var(--success); background: #f0fdf4; }
.quiz-choice.incorrect { border-color: var(--danger); background: #fef2f2; }
.quiz-choice:disabled { cursor: default; }

.quiz-explanation {
    background: #f0fdfa;
    border-left: 4px solid var(--primary);
    padding: 16px;
    border-radius: 0 var(--radius) var(--radius) 0;
    margin-bottom: 16px;
    font-size: 0.9rem;
    display: none;
}

.quiz-explanation.show { display: block; }

.quiz-next-btn, .quiz-result-btn {
    display: block;
    width: 100%;
    padding: 14px;
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s;
}

.quiz-next-btn:hover, .quiz-result-btn:hover { background: var(--primary-dark); }

/* Quiz Result */
.quiz-result {
    text-align: center;
    padding: 32px 20px;
}

.quiz-result .result-icon {
    font-size: 3rem;
    margin-bottom: 16px;
}

.quiz-result h3 {
    font-size: 1.3rem;
    margin-bottom: 8px;
}

.quiz-result .result-score {
    font-size: 2.2rem;
    font-weight: 800;
    color: var(--primary);
    margin: 16px 0;
}

.quiz-result p {
    color: var(--text-light);
    margin-bottom: 24px;
}

.btn-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.btn-primary {
    padding: 14px;
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
}

.btn-secondary {
    padding: 14px;
    background: var(--bg);
    color: var(--text);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
}

.btn-primary:hover { background: var(--primary-dark); }
.btn-secondary:hover { background: var(--border); }

/* Progress View */
.progress-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 16px 20px;
    box-shadow: var(--shadow);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 14px;
}

.progress-level-num {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.9rem;
    flex-shrink: 0;
}

.progress-level-num.done { background: var(--success); color: #fff; }

.progress-info { flex: 1; }
.progress-info h4 { font-size: 0.9rem; margin-bottom: 2px; }
.progress-info p { font-size: 0.78rem; color: var(--text-light); }

/* Footer */
.footer {
    text-align: center;
    padding: 20px;
    color: var(--text-light);
    font-size: 0.8rem;
    margin-top: auto;
}

/* Responsive */
@media (min-width: 600px) {
    .main { padding: 32px 24px; }
    .level-grid { grid-template-columns: 1fr 1fr; }
    .stats-grid { gap: 16px; }
    .dashboard-hero { padding: 48px 36px; }
    .dashboard-hero h2 { font-size: 1.8rem; }
    .btn-group { flex-direction: row; }
    .btn-group > * { flex: 1; }
}

@media (min-width: 900px) {
    .menu-btn { display: none; }
    .mobile-nav {
        display: flex;
        flex-direction: row;
        background: transparent;
        position: static;
        max-width: 1000px;
        margin: 0 auto;
        justify-content: center;
        gap: 4px;
    }
    .nav-link {
        border-bottom: none;
        border-radius: 8px;
        padding: 8px 20px;
        font-size: 0.9rem;
    }
    .header { padding-bottom: 0; }
}