:root {
    --bg: #f4f7ff;
    --panel: #ffffff;
    --text: #0f172a;
    --muted: #64748b;
    --primary: #3b82f6;
    --primary-2: #6366f1;
    --border: #e2e8f0;
    --good: #16a34a;
    --bad: #dc2626;
}

[data-theme="dark"] {
    --bg: #0b1220;
    --panel: #111a2e;
    --text: #e6edf8;
    --muted: #9fb0ca;
    --primary: #5b8dff;
    --primary-2: #7a66ff;
    --border: #223251;
    --good: #1bc26b;
    --bad: #ff6a6a;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: "Inter", sans-serif;
    background: radial-gradient(900px 500px at -20% -10%, rgba(99, 102, 241, 0.18), transparent 55%), var(--bg);
    color: var(--text);
}

.topbar {
    position: sticky;
    top: 0;
    z-index: 20;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    padding: 14px 18px;
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border);
    background: color-mix(in srgb, var(--panel) 88%, transparent);
}

.brand {
    display: flex;
    align-items: center;
    gap: 10px;
}

.brand-dot {
    width: 10px;
    height: 10px;
    border-radius: 999px;
    background: linear-gradient(135deg, var(--primary), var(--primary-2));
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.6);
}

.brand h1 {
    margin: 0;
    font-size: 1.1rem;
}

.brand p {
    margin: 0;
    color: var(--muted);
    font-size: 0.85rem;
}

.layout {
    max-width: 1320px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 240px 1fr;
    gap: 18px;
    padding: 16px;
}

.sidebar {
    display: grid;
    align-content: start;
    gap: 8px;
}

.nav-btn {
    border: 1px solid var(--border);
    background: var(--panel);
    color: var(--text);
    border-radius: 12px;
    padding: 12px 14px;
    text-align: left;
    font-weight: 600;
    cursor: pointer;
}

.nav-btn.active {
    background: linear-gradient(135deg, color-mix(in srgb, var(--primary) 22%, var(--panel)), color-mix(in srgb, var(--primary-2) 16%, var(--panel)));
    border-color: color-mix(in srgb, var(--primary) 40%, var(--border));
}

.content { min-width: 0; }

.view { display: none; }
.view.active { display: block; }

.hero {
    border: 1px solid var(--border);
    border-radius: 16px;
    background: linear-gradient(140deg, color-mix(in srgb, var(--primary) 13%, var(--panel)), var(--panel));
    padding: 18px;
    margin-bottom: 14px;
}

.hero h2 { margin: 0 0 8px; }
.hero p { margin: 0; color: var(--muted); }

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
    gap: 10px;
    margin-bottom: 12px;
}

.dashboard-toolbar {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 10px;
    align-items: center;
}

.stat {
    border: 1px solid var(--border);
    background: var(--panel);
    border-radius: 14px;
    padding: 12px;
}

.stat b { font-size: 1.35rem; display: block; margin-top: 6px; }

.panel {
    border: 1px solid var(--border);
    background: var(--panel);
    border-radius: 16px;
    padding: 16px;
    margin-bottom: 12px;
}

.section-head h2 { margin: 0 0 6px; }
.section-head p { margin: 0 0 12px; color: var(--muted); }

.controls {
    display: grid;
    grid-template-columns: 1fr auto auto;
    gap: 10px;
    align-items: center;
}

input, button {
    font: inherit;
}

input {
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 10px 12px;
    background: var(--panel);
    color: var(--text);
}

.primary-btn, .ghost-btn {
    border-radius: 12px;
    padding: 10px 12px;
    border: 1px solid var(--border);
    cursor: pointer;
    white-space: nowrap;
}

.primary-btn {
    color: white;
    border: none;
    background: linear-gradient(135deg, var(--primary), var(--primary-2));
}

.ghost-btn {
    background: var(--panel);
    color: var(--text);
}

.roadmap-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
    gap: 10px;
}

.road-step {
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 11px;
    background: color-mix(in srgb, var(--panel) 90%, var(--primary) 10%);
}

.theme-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 10px;
    margin-bottom: 12px;
}

.theme-card {
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 12px;
    background: var(--panel);
    display: grid;
    gap: 10px;
    transition: transform 0.2s ease, border-color 0.2s ease;
}

.theme-card:hover {
    transform: translateY(-2px);
    border-color: color-mix(in srgb, var(--primary) 35%, var(--border));
}

.theme-card.active {
    border-color: color-mix(in srgb, var(--primary) 55%, var(--border));
    background: linear-gradient(145deg, color-mix(in srgb, var(--panel) 80%, var(--primary) 20%), var(--panel));
}

.theme-card-head {
    display: flex;
    align-items: center;
    gap: 10px;
}

.theme-card-head h3 {
    margin: 0;
    font-size: 1rem;
}

.theme-card-head p {
    margin: 2px 0 0;
    font-size: 0.84rem;
    color: var(--muted);
}

.theme-icon {
    width: 34px;
    height: 34px;
    border-radius: 10px;
    border: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    background: color-mix(in srgb, var(--panel) 85%, var(--primary) 15%);
}

.theme-focus {
    margin: 0;
    color: var(--muted);
    font-size: 0.9rem;
}

.theme-open-btn {
    border: 1px solid var(--border);
    background: color-mix(in srgb, var(--panel) 82%, var(--primary) 18%);
    color: var(--text);
    border-radius: 10px;
    padding: 8px 10px;
    cursor: pointer;
    font-weight: 600;
}

.sheet-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
    margin-bottom: 8px;
}

.sheet-head h3 {
    margin: 0;
}

.sheet-focus {
    margin: 0 0 12px;
    color: var(--muted);
}

.sheet-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}

.sheet-block {
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 11px;
    background: color-mix(in srgb, var(--panel) 86%, var(--primary) 14%);
}

.sheet-block h4 {
    margin: 0 0 8px;
    font-size: 0.94rem;
}

.sheet-block ol,
.sheet-block ul {
    margin: 0;
    padding-left: 20px;
    display: grid;
    gap: 6px;
}

.scenario-card {
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 14px;
    margin-bottom: 12px;
}

.scenario-card h3 { margin: 0 0 8px; }
.scenario-card p { color: var(--muted); margin: 0 0 10px; }

.option-btn {
    width: 100%;
    display: block;
    text-align: left;
    border: 1px solid var(--border);
    background: var(--panel);
    color: var(--text);
    border-radius: 11px;
    padding: 10px 11px;
    margin-bottom: 8px;
    cursor: pointer;
}

.option-btn:hover { border-color: color-mix(in srgb, var(--primary) 45%, var(--border)); }

.feedback {
    display: none;
    border-radius: 10px;
    padding: 10px 11px;
    font-weight: 600;
}

.feedback.ok { display: block; background: color-mix(in srgb, var(--good) 18%, var(--panel)); color: var(--good); }
.feedback.no { display: block; background: color-mix(in srgb, var(--bad) 16%, var(--panel)); color: var(--bad); }

.gantt-wrap {
    overflow-x: auto;
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 12px;
}

.gantt-row {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 10px;
    align-items: center;
    margin-bottom: 10px;
}

.gantt-track {
    position: relative;
    height: 18px;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: color-mix(in srgb, var(--panel) 85%, var(--text) 15%);
}

.gantt-bar {
    position: absolute;
    top: 0;
    height: 100%;
    border-radius: 999px;
    color: white;
    font-size: 0.72rem;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
    white-space: nowrap;
}

.b1 { background: #7c3aed; }
.b2 { background: #2563eb; }
.b3 { background: #0d9488; }
.b4 { background: #ea580c; }
.b5 { background: #dc2626; }

.flash-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
    gap: 12px;
}

.flash {
    border: 1px solid var(--border);
    border-radius: 14px;
    min-height: 220px;
    perspective: 1000px;
    cursor: pointer;
}

.flash-inner {
    width: 100%;
    height: 100%;
    min-height: 220px;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.55s;
}

.flash.flipped .flash-inner { transform: rotateY(180deg); }

.face {
    position: absolute;
    inset: 0;
    backface-visibility: hidden;
    border-radius: 14px;
    padding: 14px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    overflow: auto;
}

.face small {
    display: inline-block;
    width: fit-content;
    padding: 3px 8px;
    border-radius: 999px;
    font-size: 0.7rem;
    font-weight: 700;
}

.q-face {
    background: var(--panel);
}

.q-face small {
    background: color-mix(in srgb, var(--primary) 16%, var(--panel));
    color: var(--primary);
}

.a-face {
    transform: rotateY(180deg);
    background: linear-gradient(145deg, #163d72, #0e2544);
    color: #e6f0ff;
}

.a-face small {
    background: rgba(255, 255, 255, 0.13);
    color: #d9e7ff;
}

.flash-answer-text {
    margin: 2px 0 0;
    font-size: 0.95rem;
    line-height: 1.5;
}

.flash-paragraphs {
    display: grid;
    gap: 8px;
}

.flash-paragraphs p {
    margin: 0;
    padding: 8px 10px;
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.09);
    border: 1px solid rgba(255, 255, 255, 0.14);
    line-height: 1.45;
}

.flash-steps {
    margin: 2px 0 0;
    padding: 0;
    list-style: none;
    display: grid;
    gap: 8px;
    counter-reset: flashStep;
}

.flash-steps li {
    position: relative;
    display: grid;
    grid-template-columns: 28px 1fr;
    gap: 8px;
    align-items: start;
    padding: 8px 10px;
    border-radius: 11px;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.18);
    animation: flashStepIn 320ms ease forwards;
    animation-delay: var(--step-delay, 0ms);
    opacity: 0;
    transform: translateY(4px);
}

.flash-steps li::before {
    counter-increment: flashStep;
    content: counter(flashStep);
    width: 24px;
    height: 24px;
    border-radius: 999px;
    background: linear-gradient(135deg, #7aa7ff, #9b7bff);
    color: white;
    font-size: 0.76rem;
    font-weight: 800;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(105, 140, 255, 0.4);
}

.flash-steps li span {
    line-height: 1.45;
    padding-top: 2px;
}

@keyframes flashStepIn {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

#quizBox h3 { margin: 6px 0 10px; }

.quiz-option {
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 10px;
    background: var(--panel);
    margin-bottom: 8px;
    cursor: pointer;
}

.quiz-option:hover { border-color: color-mix(in srgb, var(--primary) 45%, var(--border)); }

.knowledge-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 12px;
}

.knowledge-card {
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 14px;
    background: var(--panel);
}

.knowledge-card h3 { margin: 0 0 8px; }

.chip-list {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.chip {
    font-size: 0.8rem;
    padding: 6px 8px;
    border-radius: 999px;
    border: 1px solid var(--border);
    background: color-mix(in srgb, var(--panel) 80%, var(--primary) 20%);
}

@media (max-width: 980px) {
    .layout { grid-template-columns: 1fr; }
    .sidebar { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .controls { grid-template-columns: 1fr; }
    .gantt-row { grid-template-columns: 1fr; }
    .dashboard-toolbar { grid-template-columns: 1fr; }
    .sheet-grid { grid-template-columns: 1fr; }
    .sheet-head { flex-direction: column; align-items: flex-start; }
}