/* Reset & Base */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* ── Light theme (default) ─────────────────────────── */
:root {
    --color-bg: #f0f2f5;
    --color-surface: #ffffff;
    --color-surface-2: #f8f9fb;
    --color-text: #0f172a;
    --color-text-secondary: #475569;
    --color-text-muted: #94a3b8;
    --color-accent: #2563eb;
    --color-accent-hover: #1d4ed8;
    --color-border: #e2e8f0;
    --color-input-bg: #ffffff;
    --color-input-border: #cbd5e1;
    --color-up: #16a34a;
    --color-up-bg: rgba(22, 163, 74, 0.08);
    --color-down: #dc2626;
    --color-down-bg: rgba(220, 38, 38, 0.08);
    --color-partial: #d97706;
    --color-partial-bg: rgba(217, 119, 6, 0.08);
    --color-badge-up: #16a34a;
    --color-badge-up-bg: rgba(22, 163, 74, 0.12);
    --color-badge-down: #dc2626;
    --color-badge-down-bg: rgba(220, 38, 38, 0.12);
    --color-badge-partial: #d97706;
    --color-badge-partial-bg: rgba(217, 119, 6, 0.12);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.1);
    --radius: 12px;
    --radius-lg: 16px;
    --radius-pill: 50px;
    --max-width: 720px;
}

/* ── Dark theme (auto) ─────────────────────────────── */
@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --color-bg: #0b1120;
        --color-surface: #131c31;
        --color-surface-2: #1a2540;
        --color-text: #e2e8f0;
        --color-text-secondary: #94a3b8;
        --color-text-muted: #64748b;
        --color-accent: #3b82f6;
        --color-accent-hover: #60a5fa;
        --color-border: #1e2d4a;
        --color-input-bg: #131c31;
        --color-input-border: #1e2d4a;
        --color-up: #22c55e;
        --color-up-bg: rgba(34, 197, 94, 0.08);
        --color-down: #ef4444;
        --color-down-bg: rgba(239, 68, 68, 0.08);
        --color-partial: #f59e0b;
        --color-partial-bg: rgba(245, 158, 11, 0.08);
        --color-badge-up: #22c55e;
        --color-badge-up-bg: rgba(34, 197, 94, 0.1);
        --color-badge-down: #ef4444;
        --color-badge-down-bg: rgba(239, 68, 68, 0.1);
        --color-badge-partial: #f59e0b;
        --color-badge-partial-bg: rgba(245, 158, 11, 0.1);
        --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
        --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
        --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.5);
    }
}

/* ── Dark theme (manual toggle) ────────────────────── */
:root[data-theme="dark"] {
    --color-bg: #0b1120;
    --color-surface: #131c31;
    --color-surface-2: #1a2540;
    --color-text: #e2e8f0;
    --color-text-secondary: #94a3b8;
    --color-text-muted: #64748b;
    --color-accent: #3b82f6;
    --color-accent-hover: #60a5fa;
    --color-border: #1e2d4a;
    --color-input-bg: #131c31;
    --color-input-border: #1e2d4a;
    --color-up: #22c55e;
    --color-up-bg: rgba(34, 197, 94, 0.08);
    --color-down: #ef4444;
    --color-down-bg: rgba(239, 68, 68, 0.08);
    --color-partial: #f59e0b;
    --color-partial-bg: rgba(245, 158, 11, 0.08);
    --color-badge-up: #22c55e;
    --color-badge-up-bg: rgba(34, 197, 94, 0.1);
    --color-badge-down: #ef4444;
    --color-badge-down-bg: rgba(239, 68, 68, 0.1);
    --color-badge-partial: #f59e0b;
    --color-badge-partial-bg: rgba(245, 158, 11, 0.1);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.5);
}

html {
    font-size: 16px;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Inter", Helvetica, Arial, sans-serif;
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

main {
    flex: 1;
    width: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 3rem 1rem 2rem;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ── Hero ──────────────────────────────────────────── */
.hero {
    text-align: center;
    margin-bottom: 2.5rem;
    padding-top: 2rem;
}

.hero h1 {
    font-size: 2.75rem;
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -0.02em;
    margin-bottom: 0.75rem;
}

.hero .accent {
    color: var(--color-accent);
}

.hero .subtitle {
    color: var(--color-text-secondary);
    font-size: 1rem;
    line-height: 1.6;
}

/* ── Input Group (pill shape) ──────────────────────── */
.checker {
    margin-bottom: 2.5rem;
}

.input-group {
    display: flex;
    align-items: center;
    background: var(--color-input-bg);
    border: 1px solid var(--color-input-border);
    border-radius: var(--radius-pill);
    padding: 0.35rem 0.35rem 0.35rem 1.25rem;
    box-shadow: var(--shadow-md);
    transition: border-color 0.2s, box-shadow 0.2s;
}

.input-group:focus-within {
    border-color: var(--color-accent);
    box-shadow: var(--shadow-md), 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.input-icon {
    flex-shrink: 0;
    color: var(--color-text-muted);
    display: flex;
    align-items: center;
    margin-right: 0.75rem;
}

.input-group input {
    flex: 1;
    padding: 0.75rem 0.5rem;
    font-size: 1rem;
    border: none;
    outline: none;
    background: transparent;
    color: var(--color-text);
    min-width: 0;
}

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

.input-group button {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.7rem 1.5rem;
    font-size: 0.95rem;
    font-weight: 600;
    background: var(--color-accent);
    color: #fff;
    border: none;
    border-radius: var(--radius-pill);
    cursor: pointer;
    white-space: nowrap;
    transition: background 0.15s, transform 0.1s;
}

.input-group button:hover {
    background: var(--color-accent-hover);
}

.input-group button:active {
    transform: scale(0.97);
}

.input-group button:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.btn-arrow {
    font-size: 1.1rem;
}

/* ── Results ───────────────────────────────────────── */
.results {
    margin-bottom: 2rem;
}

.results:not(.visible) {
    display: none;
}

.result-card {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
}

.result-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1rem;
}

.result-identity {
    display: flex;
    align-items: center;
    gap: 0.875rem;
    min-width: 0;
}

.status-icon {
    flex-shrink: 0;
    width: 42px;
    height: 42px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.status-icon svg {
    width: 42px;
    height: 42px;
}

.status-icon-up {
    color: var(--color-up);
}

.status-icon-down {
    color: var(--color-down);
}

.status-icon-partial {
    color: var(--color-partial);
}

.result-domain {
    font-size: 1.1rem;
    font-weight: 700;
    line-height: 1.3;
}

.result-explanation {
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    line-height: 1.4;
    margin-top: 0.15rem;
}

/* ── Status Badge ──────────────────────────────────── */
.status-badge {
    flex-shrink: 0;
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    padding: 0.3rem 0.75rem;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    border-radius: var(--radius-pill);
    white-space: nowrap;
}

.status-badge::before {
    content: "";
    width: 6px;
    height: 6px;
    border-radius: 50%;
    flex-shrink: 0;
}

.badge-up {
    color: var(--color-badge-up);
    background: var(--color-badge-up-bg);
}
.badge-up::before {
    background: var(--color-badge-up);
}

.badge-down {
    color: var(--color-badge-down);
    background: var(--color-badge-down-bg);
}
.badge-down::before {
    background: var(--color-badge-down);
}

.badge-partial,
.badge-error {
    color: var(--color-badge-partial);
    background: var(--color-badge-partial-bg);
}
.badge-partial::before,
.badge-error::before {
    background: var(--color-badge-partial);
}

/* ── Metrics Row ───────────────────────────────────── */
.result-metrics {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1px;
    margin-top: 1.25rem;
    padding-top: 1.25rem;
    border-top: 1px solid var(--color-border);
}

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

.metric-label {
    font-size: 0.7rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--color-text-muted);
}

.metric-value {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--color-text);
}

.metric-ok {
    color: var(--color-up);
}

.metric-warn {
    color: var(--color-partial);
}

.metric-fail {
    color: var(--color-down);
}

/* ── Loading state ─────────────────────────────────── */
.loading .input-group button .btn-text::after {
    content: "";
    display: inline-block;
    width: 14px;
    height: 14px;
    margin-left: 8px;
    border: 2px solid rgba(255, 255, 255, 0.4);
    border-top-color: #fff;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
    vertical-align: middle;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ── FAQ ───────────────────────────────────────────── */
.faq {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--color-border);
}

.faq h2 {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 1.25rem;
}

.faq-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1rem;
}

.faq-item {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 1.25rem;
}

.faq-item h3 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 0.375rem;
}

.faq-item p {
    color: var(--color-text-secondary);
    font-size: 0.875rem;
    line-height: 1.55;
}

/* ── Theme Toggle ──────────────────────────────────── */
.theme-toggle {
    position: fixed;
    top: 1rem;
    right: 1rem;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    cursor: pointer;
    color: var(--color-text-secondary);
    box-shadow: var(--shadow-sm);
    transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.theme-toggle:hover {
    color: var(--color-text);
    border-color: var(--color-text-muted);
}

/* Show sun in dark mode, moon in light mode */
.icon-sun { display: none; }
.icon-moon { display: block; }

@media (prefers-color-scheme: dark) {
    .icon-sun { display: block; }
    .icon-moon { display: none; }
}

:root[data-theme="dark"] .icon-sun { display: block; }
:root[data-theme="dark"] .icon-moon { display: none; }
:root[data-theme="light"] .icon-sun { display: none; }
:root[data-theme="light"] .icon-moon { display: block; }

/* ── Result Actions ────────────────────────────────── */
.result-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--color-border);
}

.btn-check-again,
.btn-share {
    padding: 0.4rem 0.9rem;
    font-size: 0.8rem;
    font-weight: 600;
    border-radius: var(--radius-pill);
    cursor: pointer;
    transition: background 0.15s, color 0.15s;
    text-decoration: none;
}

.btn-check-again {
    background: var(--color-accent);
    color: #fff;
    border: none;
}

.btn-check-again:hover {
    background: var(--color-accent-hover);
}

.btn-share {
    background: transparent;
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border);
}

.btn-share:hover {
    background: var(--color-surface-2);
    color: var(--color-text);
}

/* ── History ───────────────────────────────────────── */
.history:empty {
    display: none;
}

.history-title {
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--color-text-muted);
    margin-bottom: 0.75rem;
}

.history-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 0.75rem;
}

.history-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 0.875rem 1rem;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    transition: border-color 0.15s, box-shadow 0.15s;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.5rem;
}

.history-card:hover {
    border-color: var(--color-text-muted);
    box-shadow: var(--shadow-sm);
}

.history-domain {
    font-size: 0.9rem;
    font-weight: 600;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.history-badge {
    flex-shrink: 0;
    font-size: 0.6rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    padding: 0.2rem 0.5rem;
    border-radius: var(--radius-pill);
}

.history-badge-up {
    color: var(--color-badge-up);
    background: var(--color-badge-up-bg);
}

.history-badge-down {
    color: var(--color-badge-down);
    background: var(--color-badge-down-bg);
}

.history-badge-partial,
.history-badge-error {
    color: var(--color-badge-partial);
    background: var(--color-badge-partial-bg);
}

/* ── Footer ────────────────────────────────────────── */
footer {
    text-align: center;
    padding: 1.5rem 1rem;
    color: var(--color-text-muted);
    font-size: 0.8rem;
    border-top: 1px solid var(--color-border);
}

/* ── Responsive ────────────────────────────────────── */
@media (min-width: 480px) {
    main {
        padding-top: 4rem;
    }

    .hero h1 {
        font-size: 3.5rem;
    }

    .hero .subtitle {
        font-size: 1.05rem;
    }

    .input-group button {
        padding: 0.75rem 2rem;
    }

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

@media (max-width: 520px) {
    .result-metrics {
        grid-template-columns: repeat(2, 1fr);
        gap: 1rem;
    }

    .result-header {
        flex-direction: column;
    }

    .status-badge {
        align-self: flex-start;
    }
}