:root {
    --bg: #f1f5f9;
    --surface: #ffffff;
    --surface-soft: #f8fafc;
    --border: #cbd5e1;
    --border-soft: #e2e8f0;
    --text: #0f172a;
    --muted: #64748b;
    --nav-bg: #0b1328;
    --nav-text: #ffffff;
    --primary: #0f172a;
    --primary-text: #ffffff;
    --accent: #f59e0b;
    --ok: #16a34a;
    --bad: #dc2626;
    --focus: #2563eb;
    --shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
    --radius: 18px;
    --radius-sm: 12px;
    --container-width: 1520px;
}

* {
    box-sizing: border-box;
}

html {
    font-size: 16px;
}

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: Arial, Helvetica, sans-serif;
    line-height: 1.5;
}

a {
    color: inherit;
    text-decoration: none;
}

img {
    max-width: 100%;
    height: auto;
}

.container {
    width: min(var(--container-width), calc(100vw - 64px));
    margin: 0 auto;
}

.top-space {
    margin-top: 24px;
}

.top-space-small {
    margin-top: 16px;
}

.site-header {
    background: var(--nav-bg);
    color: var(--nav-text);
    box-shadow: 0 2px 8px rgba(2, 6, 23, 0.12);
}

.nav {
    min-height: 84px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 32px;
}

.brand {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    white-space: nowrap;
}

.site-header nav {
    display: flex;
    align-items: center;
    gap: 28px;
    flex-wrap: wrap;
}

.site-header nav a {
    color: var(--nav-text);
    font-size: 1.18rem;
    font-weight: 700;
    opacity: 0.95;
}

.site-header nav a:hover {
    opacity: 1;
}

main.container {
    padding-top: 28px;
    padding-bottom: 36px;
}

h1,
h2,
h3 {
    margin: 0 0 12px;
    color: var(--text);
    line-height: 1.15;
}

h1 {
    font-size: clamp(2.6rem, 4.6vw, 4.2rem);
    font-weight: 800;
}

h2 {
    font-size: clamp(1.55rem, 2vw, 2.15rem);
    font-weight: 700;
}

h3 {
    font-size: 1.3rem;
    font-weight: 700;
}

p {
    margin: 0 0 12px;
}

.sub,
.muted {
    color: var(--muted);
}

.card {
    background: var(--surface);
    border: 1px solid var(--border-soft);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 28px 32px;
}

.card.narrow,
.form-card.narrow {
    max-width: 640px;
    margin: 0 auto;
}

.hero-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.btn,
button,
input,
select,
textarea {
    font: inherit;
}

.btn,
button {
    border: none;
    border-radius: 16px;
    background: var(--primary);
    color: var(--primary-text);
    padding: 16px 22px;
    font-size: 1.08rem;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.12s ease, opacity 0.12s ease;
}

.btn:hover,
button:hover {
    opacity: 0.96;
}

.btn:active,
button:active {
    transform: translateY(1px);
}

.btn-secondary {
    background: #e2e8f0;
    color: var(--text);
}

.btn-disabled,
button:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

label {
    display: block;
    margin-bottom: 8px;
    font-size: 1rem;
    font-weight: 700;
    color: var(--text);
}

input,
select,
textarea {
    width: 100%;
    padding: 16px 18px;
    border-radius: 16px;
    border: 1px solid var(--border);
    background: #ffffff;
    color: var(--text);
    outline: none;
    font-size: 1.08rem;
}

input::placeholder,
textarea::placeholder {
    color: var(--muted);
}

input:focus,
select:focus,
textarea:focus {
    border-color: var(--focus);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.form-card form {
    display: grid;
    gap: 16px;
}

.alert {
    border-radius: 14px;
    padding: 14px 16px;
    margin-bottom: 18px;
    font-weight: 600;
}

.alert-error {
    background: #fee2e2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

.alert-success {
    background: #dcfce7;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.row {
    display: flex;
    gap: 12px;
}

.between {
    justify-content: space-between;
}

.wrap {
    flex-wrap: wrap;
}

.align-right {
    text-align: right;
}

.inline-form {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    align-items: end;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 16px;
}

.stat-card,
.stat {
    background: var(--surface-soft);
    border: 2px solid var(--border);
    border-radius: 18px;
    padding: 18px;
}

.stat-label,
.k {
    color: #475569;
    font-size: 0.9rem;
    margin-bottom: 6px;
}

.stat-value,
.v {
    font-size: clamp(1.8rem, 2.3vw, 2.5rem);
    font-weight: 800;
    line-height: 1.1;
    color: var(--text);
}

.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
}

.mini-list {
    display: grid;
    gap: 10px;
}

.mini-item {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    padding: 14px 16px;
    background: var(--surface-soft);
    border: 1px solid var(--border);
    border-radius: 14px;
}

.table-wrap {
    overflow-x: auto;
}

.attempts-table,
table {
    width: 100%;
    border-collapse: collapse;
}

.attempts-table th,
.attempts-table td,
table th,
table td {
    text-align: left;
    padding: 12px 10px;
    border-bottom: 1px solid var(--border-soft);
    white-space: nowrap;
}

.attempts-table th,
table th {
    background: var(--surface-soft);
    color: #475569;
    font-size: 0.92rem;
}

.badge {
    display: inline-block;
    padding: 6px 10px;
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 800;
}

.badge-ok {
    background: #dcfce7;
    color: #166534;
}

.badge-bad {
    background: #fee2e2;
    color: #991b1b;
}

/* Learn/Test shared layout */

.controls {
    display: grid;
    grid-template-columns: 1.1fr 1.1fr 0.9fr 0.9fr;
    gap: 18px;
    align-items: end;
}

.target-card {
    border-left: 6px solid var(--accent);
    padding: 18px 22px;
}

.target-card .sub,
#resultMessage {
    font-size: 1.22rem;
    line-height: 1.65;
}

#resultMessage strong,
.target-card b {
    color: var(--text);
}

.lesson {
    font-size: clamp(2.2rem, 3.2vw, 3rem);
    line-height: 1.75;
    padding: 30px 26px;
    background: var(--surface-soft);
    color: var(--text);
    border: 2px solid var(--border);
    border-radius: 22px;
    min-height: 160px;
    letter-spacing: 0.01em;
}

.ok {
    color: var(--ok);
    font-weight: 800;
}

.bad {
    color: var(--bad);
    font-weight: 800;
    background: rgba(220, 38, 38, 0.1);
    border-radius: 4px;
}

.cur {
    background: #facc15;
    color: #111827;
    border-radius: 4px;
    padding: 0 2px;
}

#typing {
    font-size: clamp(1.9rem, 2.5vw, 2.5rem);
    padding: 22px 20px;
    min-height: 92px;
    border: 2px solid var(--focus);
    border-radius: 20px;
}

textarea#typing {
    min-height: 180px;
    resize: vertical;
}

.stats {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 12px;
    margin-top: 14px;
}

.lesson-list {
    display: grid;
    gap: 14px;
}

.lesson-card.locked {
    opacity: 0.7;
}

.kb {
    display: grid;
    gap: 12px;
    margin-top: 14px;
}

.kb .row {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.key {
    min-width: 60px;
    padding: 16px 14px;
    border-radius: 14px;
    border: 1px solid var(--border);
    background: #e2e8f0;
    color: var(--text);
    text-align: center;
    font-family: monospace;
    font-size: 1.15rem;
    font-weight: 800;
}

.space {
    flex: 1;
}

.hl {
    background: #facc15;
    border-color: #eab308;
    color: #111827;
}

/* index page */

.hero {
    display: grid;
    grid-template-columns: 1.4fr 1fr;
    gap: 18px;
    align-items: stretch;
}

/* responsive */

@media (max-width: 1200px) {
    .stats-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .container {
        width: min(var(--container-width), calc(100vw - 40px));
    }
}

@media (max-width: 980px) {
    .hero {
        grid-template-columns: 1fr;
    }

    .controls {
        grid-template-columns: 1fr 1fr;
    }

    .dashboard-grid {
        grid-template-columns: 1fr;
    }

    .grid-3 {
        grid-template-columns: 1fr;
    }

    .stats-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .stats {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .nav {
        align-items: flex-start;
        padding: 16px 0;
        flex-direction: column;
    }

    .site-header nav {
        gap: 18px;
    }
}

@media (max-width: 640px) {
    .container {
        width: min(var(--container-width), calc(100vw - 20px));
    }

    .card {
        padding: 18px 16px;
        border-radius: 16px;
    }

    .controls {
        grid-template-columns: 1fr;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .stats {
        grid-template-columns: 1fr 1fr;
    }

    .brand {
        font-size: 2rem;
    }

    .site-header nav a {
        font-size: 1rem;
    }

    .lesson {
        min-height: 130px;
        padding: 20px 16px;
    }

    #typing {
        font-size: 1.45rem;
        min-height: 78px;
    }

    .key {
        min-width: 46px;
        padding: 12px 10px;
        font-size: 0.95rem;
    }
}