/* CSS Variables for Theming */
:root {
    --bg: #ffffff;
    --bg-surface: #fafafa;
    --bg-elevated: #ffffff;
    --border: #e5e5e5;
    --text: #0a0a0a;
    --text-secondary: #525252;
    --text-muted: #a3a3a3;
    --accent: #2563eb;
    --accent-hover: #1d4ed8;
    --accent-light: #eff6ff;
    --success: #16a34a;
    --success-light: #dcfce7;
    --warning: #ca8a04;
    --warning-light: #fef9c3;
    --danger: #dc2626;
    --danger-light: #fee2e2;
}

.dark {
    --bg: #0a0a0a;
    --bg-surface: #171717;
    --bg-elevated: #1f1f1f;
    --border: #262626;
    --text: #fafafa;
    --text-secondary: #a3a3a3;
    --text-muted: #525252;
    --accent: #3b82f6;
    --accent-hover: #60a5fa;
    --accent-light: #1e3a5f;
    --success: #22c55e;
    --success-light: #14532d;
    --warning: #eab308;
    --warning-light: #422006;
    --danger: #ef4444;
    --danger-light: #450a0a;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--bg);
    min-height: 100vh;
    color: var(--text);
    line-height: 1.6;
    transition: background-color 0.15s ease, color 0.15s ease;
}

/* Navigation */
nav {
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    padding: 0 1.5rem;
    position: sticky;
    top: 0;
    z-index: 100;
    transition: background-color 0.15s ease, border-color 0.15s ease;
}

.nav-inner {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: center;
    height: 60px;
    position: relative;
}

.nav-brand {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text);
    text-decoration: none;
    position: absolute;
    left: 0;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 0.25rem;
    align-items: center;
}

.nav-right {
    position: absolute;
    right: 0;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    font-size: 0.875rem;
    font-weight: 500;
    transition: color 0.15s ease, background-color 0.15s ease;
    display: flex;
    align-items: center;
    gap: 0.375rem;
}

.nav-links a:hover {
    color: var(--text);
    background: var(--bg-surface);
}

.nav-links a.active {
    color: var(--accent);
}

.theme-toggle {
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 6px;
    padding: 0.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.15s ease;
    margin-left: 0.5rem;
}

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

.theme-toggle svg {
    width: 18px;
    height: 18px;
}

.icon-sun { display: none; }
.icon-moon { display: block; }
.dark .icon-sun { display: block; }
.dark .icon-moon { display: none; }

/* Container */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
}

/* Alerts */
.alert {
    padding: 0.875rem 1rem;
    border-radius: 8px;
    margin-bottom: 1rem;
    font-size: 0.875rem;
    border: 1px solid;
}

.alert-error {
    background: var(--danger-light);
    border-color: var(--danger);
    color: var(--danger);
}

.alert-success {
    background: var(--success-light);
    border-color: var(--success);
    color: var(--success);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.375rem;
    padding: 0.5rem 1rem;
    background: var(--text);
    color: var(--bg);
    text-decoration: none;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.875rem;
    font-weight: 500;
    transition: opacity 0.15s ease;
    line-height: 1.4;
}

.btn:hover { opacity: 0.85; }

.btn-primary {
    background: var(--accent);
    color: #ffffff;
}

.btn-primary:hover {
    background: var(--accent-hover);
    opacity: 1;
}

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

.btn-secondary:hover {
    background: var(--bg-surface);
    border-color: var(--text-muted);
    opacity: 1;
}

.btn-large {
    padding: 0.625rem 1.25rem;
    font-size: 0.9375rem;
}

.btn-small {
    padding: 0.375rem 0.625rem;
    font-size: 0.8125rem;
}

/* Form Elements */
input[type="text"],
input[type="number"],
select {
    background: var(--bg);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 0.625rem 0.75rem;
    border-radius: 6px;
    font-size: 0.875rem;
    width: 100%;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

input:focus,
select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-light);
}

/* Cards */
.card {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 1.5rem;
    transition: border-color 0.15s ease;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    color: var(--text);
    font-weight: 600;
    line-height: 1.3;
}

h1 { font-size: 2.25rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
}

th {
    background: var(--bg-surface);
    color: var(--text);
    padding: 0.75rem 1rem;
    text-align: left;
    font-weight: 600;
    font-size: 0.8125rem;
    text-transform: uppercase;
    letter-spacing: 0.025em;
    border-bottom: 1px solid var(--border);
}

td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--border);
    font-size: 0.875rem;
    color: var(--text);
}

tr:hover td {
    background: var(--bg-surface);
}

/* Secondary Navigation */
.secondary-nav {
    background: var(--bg-surface);
    border-bottom: 1px solid var(--border);
    padding: 0;
    margin: -2rem calc(-50vw + 50%) 2rem calc(-50vw + 50%);
    width: 100vw;
    position: sticky;
    top: 60px;
    z-index: 50;
}

.secondary-nav-inner {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 1.5rem;
    display: flex;
    gap: 0.25rem;
    height: 48px;
    align-items: center;
}

.secondary-nav a {
    color: var(--text-secondary);
    text-decoration: none;
    padding: 0.5rem 0.875rem;
    border-radius: 6px;
    font-size: 0.875rem;
    font-weight: 500;
    transition: color 0.15s ease, background-color 0.15s ease;
    display: flex;
    align-items: center;
    gap: 0.375rem;
}

.secondary-nav a:hover {
    color: var(--text);
    background: var(--bg-elevated);
}

.secondary-nav a.active {
    color: var(--accent);
}

/* Page Header */
.page-header {
    margin-bottom: 2rem;
}

.page-header h1 {
    margin-bottom: 0.5rem;
}

.page-header p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: 8px;
}

.empty-state h2 {
    margin-bottom: 0.75rem;
}

.empty-state p {
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

/* Score Cells */
.score-cell {
    text-align: center;
}

.score-main {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text);
}

.score-detail {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* Device Link */
.device-link {
    color: var(--text);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.15s ease;
}

.device-link:hover {
    color: var(--accent);
}

/* Cell Backgrounds */
.cell-easy { background: var(--success-light); }
.cell-difficult { background: var(--danger-light); }
.cell-warning { background: var(--warning-light); }
.cell-accent { background: var(--accent-light); }