:root {
    --bg: #f6f7fb;
    --surface: #ffffff;
    --muted: #667085;
    --text: #111827;
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --border: #e5e7eb;
    --success: #047857;
    --error: #b42318;
}

* {
    box-sizing: border-box;
}

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

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

.site-header {
    position: sticky;
    top: 0;
    z-index: 10;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 32px;
    background: rgba(255, 255, 255, 0.94);
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(12px);
}

.brand {
    font-size: 22px;
    font-weight: 800;
    color: var(--primary);
}

.nav {
    display: flex;
    gap: 18px;
    color: var(--muted);
    font-weight: 600;
}

.nav-link:hover {
    color: var(--primary);
}

.page {
    min-height: calc(100vh - 140px);
}

.hero {
    padding: 96px 32px;
    background: linear-gradient(135deg, #eef4ff, #ffffff);
}

.hero-content,
.section {
    width: min(1120px, 100%);
    margin: 0 auto;
}

.section {
    padding: 56px 32px;
}

.section.narrow {
    width: min(780px, 100%);
}

.section.compact {
    padding-bottom: 0;
}

.muted {
    background: #eef2ff;
}

.eyebrow {
    color: var(--primary);
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.08em;
}

h1 {
    max-width: 860px;
    margin: 0 0 20px;
    font-size: clamp(36px, 5vw, 64px);
    line-height: 1.05;
}

h2 {
    margin: 0 0 18px;
    font-size: 30px;
}

h3 {
    margin: 0 0 10px;
}

.lead {
    max-width: 760px;
    color: var(--muted);
    font-size: 20px;
    line-height: 1.6;
}

.muted-text {
    color: var(--muted);
}

.grid {
    display: grid;
    gap: 20px;
}

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

.grid.three {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

.card {
    display: block;
    padding: 24px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 22px;
    box-shadow: 0 12px 30px rgba(15, 23, 42, 0.06);
}

.link-card:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}

.actions,
.form-row {
    display: flex;
    gap: 12px;
    align-items: center;
    flex-wrap: wrap;
}

.button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 44px;
    padding: 0 18px;
    color: #ffffff;
    background: var(--primary);
    border: 0;
    border-radius: 12px;
    cursor: pointer;
    font-weight: 700;
}

.button:hover {
    background: var(--primary-dark);
}

.button.secondary {
    color: var(--primary);
    background: #dbeafe;
}

.button.danger {
    background: var(--error);
}

.button.danger:hover {
    background: #7f1d1d;
}

.input {
    min-width: min(420px, 100%);
    min-height: 44px;
    padding: 0 14px;
    border: 1px solid var(--border);
    border-radius: 12px;
    font-size: 16px;
}

.textarea {
    width: 100%;
    min-height: 120px;
    padding: 12px 14px;
    border: 1px solid var(--border);
    border-radius: 12px;
    font: inherit;
    resize: vertical;
}

.form-field {
    display: grid;
    gap: 8px;
    margin-bottom: 16px;
}

.form-field label {
    color: var(--muted);
    font-size: 14px;
    font-weight: 800;
}

.api-key-form,
.api-key-delete-confirm {
    margin-top: 18px;
}

.modal-overlay {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    background: rgba(15, 23, 42, 0.45);
    backdrop-filter: blur(4px);
}

.modal-card {
    width: min(640px, 100%);
    max-height: calc(100vh - 48px);
    margin: 0;
    overflow-y: auto;
}

.message {
    margin-top: 16px;
}

.success {
    color: var(--success);
    font-weight: 700;
}

.error {
    color: var(--error);
    font-weight: 700;
}

.back-link {
    color: var(--primary);
    font-weight: 800;
}

.chart {
    margin: 24px 0;
}

.data-table {
    width: 100%;
    margin-top: 14px;
    overflow: hidden;
    border: 1px solid var(--border);
    border-collapse: separate;
    border-spacing: 0;
    border-radius: 14px;
    font-size: 14px;
}

.data-table th,
.data-table td {
    padding: 12px 14px;
    border-bottom: 1px solid var(--border);
    text-align: left;
    vertical-align: top;
}

.data-table th {
    color: var(--muted);
    background: #f9fafb;
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

.data-table tr:last-child td {
    border-bottom: 0;
}

.data-table tbody tr:hover {
    background: #f9fafb;
}

.table-actions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

.table-action {
    padding: 0;
    color: var(--primary);
    background: transparent;
    border: 0;
    cursor: pointer;
    font: inherit;
    font-weight: 700;
}

.table-action:hover {
    text-decoration: underline;
}

.tariff-grid {
    margin: 18px 0;
}

.tariff-card {
    gap: 8px;
    width: 100%;
    color: var(--text);
    background: var(--surface);
    cursor: pointer;
    font: inherit;
    text-align: left;
}

.tariff-card:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}

.tariff-card strong,
.tariff-card span {
    display: block;
}

.danger-text {
    color: var(--error);
}

.site-footer {
    padding: 28px 32px;
    color: var(--muted);
    text-align: center;
    border-top: 1px solid var(--border);
}

@media (max-width: 820px) {
    .site-header,
    .nav {
        align-items: flex-start;
        flex-direction: column;
    }

    .grid.two,
    .grid.three {
        grid-template-columns: 1fr;
    }
}