:root {
    --bg-color: #ffffff;
    --surface-color: #f9fafb;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --danger-color: #ef4444;
    --success-color: #10b981;
    --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    -webkit-font-smoothing: antialiased;
}

.font-tabular {
    font-variant-numeric: tabular-nums;
    font-family: var(--font-mono);
}

/* Landing Clock */
.hero-clock {
    font-size: clamp(4rem, 15vw, 10rem);
    font-weight: 800;
    letter-spacing: -0.05em;
    line-height: 1;
    color: var(--text-primary);
}

/* Cards & Containers */
.card-precise {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    transition: all 0.2s ease;
}

.card-precise:hover {
    border-color: var(--accent-color);
    background: #fff;
    box-shadow: 0 4px 12px rgba(0,0,0,0.03);
}

.btn-precise {
    border-radius: 4px;
    font-weight: 500;
    padding: 0.5rem 1rem;
    transition: all 0.1s ease;
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.05em;
}

/* Timer Display */
.timer-display {
    font-size: clamp(3rem, 10vw, 6rem);
    font-weight: 700;
    color: var(--text-primary);
}

.timer-sub-display {
    font-size: 1.5rem;
    color: var(--text-secondary);
}

/* Table */
.table-precise {
    font-size: 0.875rem;
}

.table-precise th {
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    font-size: 0.7rem;
    letter-spacing: 0.05em;
    border-bottom: 2px solid var(--border-color);
}

.badge-best {
    background-color: var(--success-color);
    color: white;
    font-size: 0.65rem;
    padding: 2px 6px;
    border-radius: 2px;
}

/* SPA Transitions */
.view-section {
    display: none;
}

.view-section.active {
    display: block;
}

/* Forms */
.form-control-precise {
    border-radius: 4px;
    border: 1px solid var(--border-color);
    font-size: 0.875rem;
    padding: 0.4rem 0.75rem;
}

.form-control-precise:focus {
    border-color: var(--accent-color);
    box-shadow: none;
}

#session-title {
    background-color: var(--surface-color);
    border-width: 0 0 2px 0;
    border-radius: 0;
    padding-left: 0;
}

#session-title:focus {
    background-color: transparent;
    border-color: var(--accent-color);
}

/* Activity Builder */
#custom-builder {
    background: var(--surface-color);
    padding: 1.5rem;
    border: 1px dashed var(--border-color);
    border-radius: 8px;
}

.activity-row {
    transition: transform 0.2s ease;
    box-shadow: 0 2px 4px rgba(0,0,0,0.02);
}

.activity-row:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.05);
}

/* Options Dropdown */
.dropdown-menu {
    box-shadow: 0 10px 25px rgba(0,0,0,0.1) !important;
    border: 1px solid var(--border-color);
}

.dropdown-header {
    color: var(--text-primary);
    font-weight: 700;
    letter-spacing: 0.1em;
}

/* Utility */
.tracking-widest { letter-spacing: 0.1em; }
.tracking-wider { letter-spacing: 0.05em; }
.fs-small { font-size: 0.75rem; }
.fs-tiny { font-size: 0.65rem; }
.cursor-pointer { cursor: pointer; }

/* Alerts / Finishes */
.timer-finish {
    animation: flash 1s infinite;
}

@keyframes flash {
    0% { opacity: 1; }
    50% { opacity: 0.5; }
    100% { opacity: 1; }
}

/* Settings Switches */
.form-check-input:checked {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
}