/* === Sol2 Training — Dark Theme === */
:root {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-card: #1e3a5f;
    --bg-input: #0f1629;
    --text-primary: #e0e0e0;
    --text-secondary: #888;
    --text-muted: #666;
    --accent: #4fc3f7;
    --accent-hover: #81d4fa;
    --green: #4caf50;
    --orange: #ff9800;
    --red: #ff5252;
    --purple: #ce93d8;
    --border: #2a3a5e;
    --radius: 8px;
    --radius-lg: 12px;
    --shadow: 0 2px 8px rgba(0,0,0,0.3);
    --max-width: 960px;
    --nav-height: 56px;
}

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

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

/* === Screens === */
.screen { min-height: 100vh; }

/* === Login === */
.login-box {
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    background: var(--bg-secondary);
    padding: 48px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    text-align: center;
    width: 100%;
    max-width: 400px;
}
.login-box h1 { color: var(--accent); margin-bottom: 4px; font-size: 28px; }
.login-box .subtitle { color: var(--text-secondary); margin-bottom: 32px; }
.login-box form { display: flex; flex-direction: column; gap: 12px; }

/* === Inputs & Buttons === */
input[type="text"], input[type="password"], input[type="email"], input[type="search"] {
    background: var(--bg-input);
    border: 1px solid var(--border);
    color: var(--text-primary);
    padding: 12px 16px;
    border-radius: var(--radius);
    font-size: 14px;
    outline: none;
    transition: border-color 0.2s;
}
input:focus { border-color: var(--accent); }

.btn {
    padding: 10px 24px;
    border: none;
    border-radius: var(--radius);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
}
.btn:active { transform: scale(0.98); }
.btn-primary { background: var(--accent); color: var(--bg-primary); }
.btn-primary:hover { background: var(--accent-hover); }
.btn-small { padding: 6px 12px; font-size: 12px; background: transparent; color: var(--text-secondary); border: 1px solid var(--border); }
.btn-small:hover { border-color: var(--accent); color: var(--accent); }
.btn-green { background: var(--green); color: #fff; }
.btn-orange { background: var(--orange); color: #fff; }
.btn-red { background: var(--red); color: #fff; }
.btn-muted { background: var(--text-muted); color: #fff; }
.error-msg { color: var(--red); font-size: 13px; margin-top: 8px; }

/* === Top Navigation === */
.top-nav {
    display: flex;
    align-items: center;
    background: var(--bg-secondary);
    padding: 0 24px;
    height: var(--nav-height);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}
.nav-brand { color: var(--accent); font-weight: 700; font-size: 18px; margin-right: 32px; white-space: nowrap; }
.nav-links { display: flex; gap: 4px; flex: 1; }
.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: var(--radius);
    font-size: 14px;
    transition: color 0.2s, background 0.2s;
}
.nav-link:hover { color: var(--text-primary); background: rgba(255,255,255,0.05); }
.nav-link.active { color: var(--accent); background: rgba(79,195,247,0.1); }
.nav-user { display: flex; align-items: center; gap: 12px; margin-left: auto; }
.nav-user span { color: var(--text-secondary); font-size: 13px; }

/* === Content Area === */
.content-area {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 32px 24px;
}

/* === Module Tiles (Dashboard) === */
.module-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 16px; }
.module-tile {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    text-align: center;
    cursor: pointer;
    transition: border-color 0.2s, transform 0.2s;
}
.module-tile:hover { border-color: var(--accent); transform: translateY(-2px); }
.module-tile .tile-icon { font-size: 36px; margin-bottom: 12px; }
.module-tile .tile-title { color: var(--accent); font-size: 16px; font-weight: 600; margin-bottom: 4px; }
.module-tile .tile-info { color: var(--text-secondary); font-size: 12px; margin-bottom: 12px; }

/* === Progress Bar === */
.progress-bar { background: #333; height: 6px; border-radius: 3px; overflow: hidden; margin-top: 8px; }
.progress-bar .fill { height: 100%; border-radius: 3px; transition: width 0.3s; }
.progress-bar .fill-green { background: var(--green); }
.progress-bar .fill-accent { background: var(--accent); }
.progress-segmented { display: flex; height: 6px; border-radius: 3px; overflow: hidden; gap: 1px; }
.progress-segmented .seg-correct { background: var(--green); }
.progress-segmented .seg-wrong { background: var(--red); }
.progress-segmented .seg-open { background: #333; }

/* === Cards / Deck List === */
.deck-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; }
.deck-card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 20px;
    cursor: pointer;
    transition: transform 0.2s;
    border: 1px solid transparent;
}
.deck-card:hover { transform: translateY(-2px); border-color: var(--accent); }
.deck-card .deck-name { color: var(--accent); font-size: 15px; font-weight: 600; }
.deck-card .deck-info { color: var(--text-secondary); font-size: 12px; margin-top: 4px; }
.deck-card .deck-due { color: var(--orange); font-size: 12px; margin-top: 8px; }

/* === Flashcard Study === */
.study-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }
.study-deck-name { color: var(--accent); font-size: 14px; }
.study-counter { color: var(--text-muted); font-size: 13px; }
.study-stats { display: flex; gap: 16px; font-size: 13px; }
.stat-correct { color: var(--green); }
.stat-wrong { color: var(--red); }
.stat-open { color: var(--text-muted); }

.flashcard {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px;
    min-height: 200px;
}
.flashcard .card-meta { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; }
.flashcard .card-level {
    background: var(--bg-input);
    color: var(--accent);
    padding: 3px 10px;
    border-radius: 4px;
    font-size: 11px;
    text-transform: uppercase;
}
.flashcard .card-last-review { color: var(--text-muted); font-size: 11px; }
.flashcard .card-question { color: #fff; font-size: 18px; line-height: 1.6; margin-bottom: 16px; }
.flashcard .card-answer {
    border-top: 1px solid var(--border);
    padding-top: 16px;
    color: var(--text-primary);
    font-size: 14px;
    line-height: 1.7;
}
.flashcard .card-answer-label { color: var(--green); font-size: 11px; text-transform: uppercase; letter-spacing: 1px; margin-bottom: 8px; }
.card-answer-hidden { text-align: center; padding: 24px 0; }
.rating-buttons { display: flex; gap: 8px; justify-content: center; margin-top: 20px; }
.rating-buttons .btn { min-width: 80px; }

/* === Code blocks === */
code {
    background: var(--bg-input);
    padding: 2px 6px;
    border-radius: 4px;
    color: var(--accent);
    font-family: 'Consolas', 'Fira Code', monospace;
    font-size: 0.9em;
}
pre { background: var(--bg-input); padding: 16px; border-radius: var(--radius); overflow-x: auto; margin: 12px 0; }
pre code { background: none; padding: 0; }

/* === Tutorial === */
.tutorial-list { display: flex; flex-direction: column; gap: 12px; }
.tutorial-item {
    display: flex; align-items: center; gap: 16px;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 20px;
    cursor: pointer;
    transition: border-color 0.2s;
}
.tutorial-item:hover { border-color: var(--accent); }
.tutorial-item .tut-number { color: var(--accent); font-size: 24px; font-weight: 700; min-width: 40px; }
.tutorial-item .tut-title { color: #fff; font-size: 15px; }
.tutorial-item .tut-info { color: var(--text-secondary); font-size: 12px; }
.tutorial-item .tut-check { color: var(--green); font-size: 20px; margin-left: auto; }

.tutorial-content { background: var(--bg-secondary); border-radius: var(--radius-lg); padding: 32px; border: 1px solid var(--border); line-height: 1.8; }
.tutorial-content h1, .tutorial-content h2, .tutorial-content h3 { color: var(--accent); margin: 24px 0 12px; }
.tutorial-content h1 { font-size: 24px; }
.tutorial-content h2 { font-size: 20px; }
.tutorial-content h3 { font-size: 16px; }
.tutorial-content p { margin-bottom: 12px; }
.tutorial-content table { width: 100%; border-collapse: collapse; margin: 12px 0; }
.tutorial-content th, .tutorial-content td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; }
.tutorial-content th { background: var(--bg-input); color: var(--accent); }

/* === Quiz === */
.quiz-option {
    display: block;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 14px 20px;
    margin-bottom: 8px;
    cursor: pointer;
    transition: border-color 0.2s;
    width: 100%;
    text-align: left;
    color: var(--text-primary);
    font-size: 14px;
}
.quiz-option:hover { border-color: var(--accent); }
.quiz-option.selected { border-color: var(--accent); background: rgba(79,195,247,0.1); }
.quiz-option.correct { border-color: var(--green); background: rgba(76,175,80,0.1); }
.quiz-option.wrong { border-color: var(--red); background: rgba(255,82,82,0.1); }

/* === Cheat Sheets === */
.sheet-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 12px; }
.sheet-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    cursor: pointer;
    transition: border-color 0.2s;
}
.sheet-card:hover { border-color: var(--accent); }
.sheet-card .sheet-title { color: var(--accent); font-weight: 600; }
.sheet-card .sheet-cat { color: var(--text-secondary); font-size: 12px; margin-top: 4px; }
.sheet-content { background: var(--bg-secondary); border-radius: var(--radius-lg); padding: 32px; border: 1px solid var(--border); line-height: 1.8; }

/* === Admin === */
.admin-section { margin-bottom: 32px; }
.admin-section h2 { color: var(--accent); margin-bottom: 16px; }
.user-table { width: 100%; border-collapse: collapse; }
.user-table th, .user-table td { border: 1px solid var(--border); padding: 10px 14px; text-align: left; }
.user-table th { background: var(--bg-input); color: var(--accent); font-size: 13px; }

/* === Page Headers === */
.page-header { margin-bottom: 24px; }
.page-header h1 { font-size: 22px; color: #fff; }
.page-header p { color: var(--text-secondary); font-size: 14px; margin-top: 4px; }

/* === Misc === */
.search-bar { margin-bottom: 20px; }
.search-bar input { width: 100%; max-width: 400px; }
.back-link { display: inline-block; color: var(--text-secondary); text-decoration: none; font-size: 13px; margin-bottom: 16px; }
.back-link:hover { color: var(--accent); }
.empty-state { text-align: center; padding: 48px 0; color: var(--text-secondary); }
.loading { text-align: center; padding: 48px 0; color: var(--text-muted); }

/* === Responsive === */
@media (max-width: 768px) {
    .top-nav { flex-wrap: wrap; height: auto; padding: 8px 16px; gap: 8px; }
    .nav-brand { font-size: 16px; margin-right: 0; }
    .nav-links { order: 3; width: 100%; overflow-x: auto; gap: 0; padding-bottom: 4px; }
    .nav-link { padding: 6px 10px; font-size: 13px; white-space: nowrap; }
    .nav-user { margin-left: auto; }
    .content-area { padding: 20px 16px; }
    .module-grid { grid-template-columns: 1fr 1fr; }
    .deck-grid { grid-template-columns: 1fr; }
    .flashcard .card-question { font-size: 16px; }
    .rating-buttons { flex-wrap: wrap; }
    .login-box { padding: 32px 24px; margin: 0 16px; }
}
@media (max-width: 480px) {
    .module-grid { grid-template-columns: 1fr; }
}