:root {
    --bg-color: #f4f4f5;
    --bg-card: #ffffff;
    --bg-toolbar: #ffffff;
    --text-color: #111827;
    --text-muted: #6b7280;
    --border-color: #e5e7eb;
    --primary-color: #1d4ed8;        /* dark blue theme */
    --primary-soft: #dbeafe;
    --primary-soft-strong: #bfdbfe;
    --danger-color: #b91c1c;
    --danger-soft: #fee2e2;
    --correct-bg: #dcfce7;
    --correct-border: #16a34a;
    --wrong-bg: #fee2e2;
    --wrong-border: #b91c1c;
    --shadow-soft: 0 10px 25px rgba(15, 23, 42, 0.08);
    --radius-card: 16px;
    --radius-pill: 999px;
    --transition-fast: 0.15s ease-out;
    --font-main: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
    height: 100%;
}

body {
    font-family: var(--font-main);
    background: radial-gradient(circle at top left, #e5edff 0, #f9fafb 45%, #eef2ff 100%);
    color: var(--text-color);
}

/* Layout */
.page {
    min-height: 100vh;
    max-width: 1120px;
    margin: 0 auto;
    padding: 1.6rem 1.2rem 2rem;
}

/* Toolbar / header */
.toolbar {
    display: flex;
    justify-content: space-between;
    gap: 1.2rem;
    align-items: center;
    margin-bottom: 1.6rem;
    padding: 1rem 1.2rem;
    border-radius: 20px;
    background: rgba(255, 255, 255, 0.92);
    box-shadow: var(--shadow-soft);
    backdrop-filter: blur(10px);
}

.toolbar h1 {
    margin: 0;
    font-size: 1.4rem;
    letter-spacing: 0.02em;
}

.subtitle {
    margin-top: 0.25rem;
    color: var(--text-muted);
}

.small {
    font-size: 0.85rem;
    line-height: 1.4;
}

/* Cards */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-card);
    padding: 1.4rem 1.6rem;
    margin-bottom: 1.4rem;
    box-shadow: var(--shadow-soft);
    border: 1px solid var(--border-color);
}

.card h2 {
    margin-top: 0;
    margin-bottom: 0.6rem;
    font-size: 1.15rem;
}

.card h3 {
    margin-top: 0.5rem;
    margin-bottom: 0.4rem;
    font-size: 1rem;
}

/* Two columns layout (portal) */
.two-columns {
    display: grid;
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1.2fr);
    gap: 1.2rem;
}

@media (max-width: 880px) {
    .two-columns {
        grid-template-columns: minmax(0, 1fr);
    }
}

/* Buttons: base style for ALL buttons */
button {
    font-family: inherit;
    border: none;
    border-radius: var(--radius-pill);
    padding: 0.45rem 1.1rem;
    font-size: 0.9rem;
    cursor: pointer;
    background: var(--primary-color);
    color: #ffffff;
    font-weight: 500;
    letter-spacing: 0.01em;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    transition:
        background var(--transition-fast),
        transform var(--transition-fast),
        box-shadow var(--transition-fast),
        color var(--transition-fast);
    box-shadow: 0 7px 18px rgba(37, 99, 235, 0.3);
}

button:hover {
    background: #1e40af;
    transform: translateY(-1px);
    box-shadow: 0 10px 24px rgba(37, 99, 235, 0.35);
}

button:active {
    transform: translateY(0);
    box-shadow: 0 5px 12px rgba(37, 99, 235, 0.25);
}

button:disabled {
    opacity: 0.55;
    cursor: not-allowed;
    box-shadow: none;
}

/* Toolbar buttons container */
.toolbar-buttons {
    display: flex;
    gap: 0.6rem;
    align-items: center;
}

/* Toolbar buttons - wider than default */
.toolbar-btn,
.theme-toggle {
    min-width: 100px;
    padding: 0.5rem 1.4rem;
    justify-content: center;
}

/* Inputs & selects */
input[type="text"],
input[type="number"],
select {
    font-family: inherit;
    border-radius: var(--radius-pill);
    border: 1px solid var(--border-color);
    padding: 0.4rem 0.8rem;
    font-size: 0.9rem;
    margin: 0.3rem 0 0.7rem;
    min-width: 200px;
    background: #ffffff;
    color: var(--text-color);
    box-shadow: 0 4px 10px rgba(15, 23, 42, 0.04);
    outline: none;
    transition:
        border-color var(--transition-fast),
        box-shadow var(--transition-fast),
        background var(--transition-fast);
}

input[type="text"]:focus,
input[type="number"]:focus,
select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 1px rgba(37, 99, 235, 0.25);
}

/* Error / info text */
#error {
    margin-top: 0.4rem;
    color: var(--danger-color);
    font-size: 0.86rem;
}

/* Tables (attempts) */
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
}

th,
td {
    padding: 0.5rem 0.6rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

thead th {
    font-weight: 600;
    color: var(--text-muted);
    background: #f9fafb;
}

/* Utility */
.hidden {
    display: none !important;
}

/* Quiz-specific helpers used across pages */
.question {
    margin-bottom: 1rem;
    padding: 0.75rem 0.9rem;
    border-radius: 0.9rem;
    border: 1px solid var(--border-color);
    background: #f9fafb;
}

.question-title {
    font-weight: 500;
    margin-bottom: 0.35rem;
}

.question-title span {
    display: inline-flex;
    width: 1.6rem;
    height: 1.6rem;
    border-radius: var(--radius-pill);
    align-items: center;
    justify-content: center;
    font-size: 0.8rem;
    margin-right: 0.4rem;
    background: var(--primary-soft);
    color: var(--primary-color);
}

.options {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.option-label {
    display: flex;
    align-items: center;
    gap: 0.45rem;
    padding: 0.35rem 0.55rem;
    border-radius: var(--radius-pill);
    cursor: pointer;
    transition:
        background var(--transition-fast),
        transform var(--transition-fast),
        box-shadow var(--transition-fast),
        border-color var(--transition-fast),
        color var(--transition-fast);
    border: 1px solid transparent;
}

.option-label:hover {
    background: #eff6ff;
}

.option-label input[type="radio"] {
    accent-color: var(--primary-color);
}

/* Feedback colors (work in light and dark) */
.correct-option {
    background: var(--correct-bg) !important;
    border-color: var(--correct-border) !important;
    color: #14532d !important;
}

.wrong-option {
    background: var(--wrong-bg) !important;
    border-color: var(--wrong-border) !important;
    color: #7f1d1d !important;
}

/* Result text under quiz */
#result {
    margin-top: 0.6rem;
    font-weight: 500;
}

/* Links */
a {
    color: var(--primary-color);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* ------------------------------------------------------------------
   DARK THEME
   ------------------------------------------------------------------ */

body.dark {
    background: radial-gradient(circle at top left, #020617 0, #020617 40%, #020617 100%);
    color: #e5e7eb;
}

body.dark .toolbar {
    background: rgba(15, 23, 42, 0.96);
    border: 1px solid #1f2937;
}

body.dark .card {
    background: #020617;
    border-color: #111827;
    box-shadow: 0 14px 30px rgba(0, 0, 0, 0.7);
}

body.dark h1,
body.dark h2,
body.dark h3 {
    color: #e5e7eb;
}

body.dark .subtitle,
body.dark .small {
    color: #9ca3af;
}

/* Inputs / selects in dark */
body.dark input[type="text"],
body.dark input[type="number"],
body.dark select {
    background: #020617;
    border-color: #1f2937;
    color: #f3f4f6;
    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.7);
}

body.dark input[type="text"]:focus,
body.dark input[type="number"]:focus,
body.dark select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 1px rgba(59, 130, 246, 0.65);
}

/* Buttons in dark mode: ALL buttons, including toolbar & theme */
body.dark button {
    background: #e5e7eb;
    color: var(--primary-color);
    box-shadow: 0 10px 22px rgba(0, 0, 0, 0.8);
}

body.dark button:hover {
    background: #f9fafb;
    color: #1e40af;
    box-shadow: 0 12px 26px rgba(0, 0, 0, 0.9);
}

/* Questions & options in dark */
body.dark .question {
    background: #020617;
    border-color: #111827;
}

body.dark .question-title span {
    background: rgba(37, 99, 235, 0.18);
    color: #bfdbfe;
}

body.dark .option-label {
    border-color: transparent;
}

body.dark .option-label:hover {
    background: rgba(15, 23, 42, 0.9);
}

/* Feedback (correct / wrong) in dark */
body.dark .correct-option {
    background: #166534 !important;
    border-color: #22c55e !important;
    color: #e5f9ed !important;
}

body.dark .wrong-option {
    background: #7f1d1d !important;
    border-color: #f97373 !important;
    color: #fee2e2 !important;
}

/* Tables in dark */
body.dark table {
    background: transparent;
}

body.dark thead th {
    background: #020617;
    color: #9ca3af;
}

body.dark th,
body.dark td {
    border-bottom-color: #1f2937;
}

/* Links in dark */
body.dark a {
    color: #93c5fd;
}

body.dark a:hover {
    color: #bfdbfe;
}