:root {
    --bg-color: #f8fafc;
    --card-bg: white;
    --text-main: #0f172a;
    --text-h1: #1e293b;
    --text-h2: #334155;
    --text-muted: #475569;
    --text-light: #64748b;
    --text-lighter: #94a3b8;
    --primary: #2563eb;
    --surface-bg: #f1f5f9;
    --surface-focus: #eff6ff;
    --minus-bg: #fee2e2;
    --minus-text: #b91c1c;
    --plus-bg: #dcfce3;
    --plus-text: #15803d;
    --border-color: #e2e8f0;
}

body.theme-dark {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-main: #f8fafc;
    --text-h1: #f1f5f9;
    --text-h2: #e2e8f0;
    --text-muted: #cbd5e1;
    --text-light: #94a3b8;
    --text-lighter: #64748b;
    --primary: #3b82f6;
    --surface-bg: #334155;
    --surface-focus: #475569;
    --minus-bg: #7f1d1d;
    --minus-text: #fca5a5;
    --plus-bg: #14532d;
    --plus-text: #86efac;
    --border-color: #334155;
}

@media (prefers-color-scheme: dark) {
    body:not(.theme-light) {
        --bg-color: #0f172a;
        --card-bg: #1e293b;
        --text-main: #f8fafc;
        --text-h1: #f1f5f9;
        --text-h2: #e2e8f0;
        --text-muted: #cbd5e1;
        --text-light: #94a3b8;
        --text-lighter: #64748b;
        --primary: #3b82f6;
        --surface-bg: #334155;
        --surface-focus: #475569;
        --minus-bg: #7f1d1d;
        --minus-text: #fca5a5;
        --plus-bg: #14532d;
        --plus-text: #86efac;
        --border-color: #334155;
    }
}

/* Basic styles */
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-main);
    -webkit-tap-highlight-color: transparent;
    transition: background-color 0.3s, color 0.3s;
}

#app {
    max-width: 600px;
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

header {
    text-align: center;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
    position: relative;
}

h1 {
    margin: 0;
    font-size: 1.5rem;
    color: var(--text-h1);
}

h2 {
    font-size: 1.25rem;
    color: var(--text-h2);
    margin-top: 0;
    margin-bottom: 1rem;
}

/* Pace Display Section */
.pace-display-section {
    display: flex;
    flex-direction: column;
    align-items: center;
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 1rem;
    box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

.unit-toggle {
    display: flex;
    background-color: var(--surface-bg);
    border-radius: 0.5rem;
    padding: 0.25rem;
    margin-bottom: 1.5rem;
}

.toggle-btn {
    border: none;
    background: transparent;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-light);
    border-radius: 0.375rem;
    cursor: pointer;
    min-height: 48px; /* Mobile accessibility */
}

.toggle-btn.active {
    background-color: var(--card-bg);
    color: var(--primary);
    box-shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1);
}

.current-pace {
    font-size: 4rem;
    font-weight: 700;
    line-height: 1;
    color: var(--primary);
    margin-bottom: 1rem;
    display: flex;
    align-items: baseline;
    justify-content: center;
}

.time-input {
    font-family: inherit;
    font-size: inherit;
    font-weight: inherit;
    color: inherit;
    background: transparent;
    border: none;
    padding: 0;
    margin: 0;
    width: 2.5ch;
    text-align: center;
    -moz-appearance: textfield;
}

.time-input:focus {
    outline: none;
    background: var(--surface-focus);
    border-radius: 0.5rem;
}

.unit-label {
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--text-light);
    margin-left: 0.25rem;
}

.converted-pace {
    font-size: 1.25rem;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.converted-pace .label {
    font-weight: 500;
}

#converted-time {
    font-weight: 700;
    color: var(--text-main);
}

/* Controls Section */
.controls-section {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.control-row {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
}

.adjust-btn {
    flex: 1;
    border: none;
    border-radius: 0.75rem;
    font-size: 1.25rem;
    font-weight: 600;
    padding: 1rem 0;
    cursor: pointer;
    min-height: 60px; /* Large tap targets for running */
    touch-action: manipulation;
    transition: background-color 0.1s, transform 0.1s;
}

.adjust-btn:active {
    transform: scale(0.95);
}

.adjust-btn.minus {
    background-color: var(--minus-bg);
    color: var(--minus-text);
}

.adjust-btn.plus {
    background-color: var(--plus-bg);
    color: var(--plus-text);
}

/* Race Times Section */
.race-times-section {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 1rem;
    box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

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

.race-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--surface-bg);
}

.race-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.race-name {
    font-weight: 500;
    color: var(--text-muted);
    font-size: 1.1rem;
}

.race-time {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text-main);
}

.race-time-input {
    font-family: inherit;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text-main);
    background: transparent;
    border: none;
    text-align: right;
    width: 6ch;
    padding: 0;
    margin: 0;
}
.race-time-input:focus {
    outline: none;
    background: var(--surface-focus);
    border-radius: 0.25rem;
}

@media (min-width: 480px) {
    .race-grid {
        grid-template-columns: 1fr 1fr;
        gap: 1.5rem;
    }
}

/* Tabs */
.tab-navigation {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 1rem;
}

.tab-nav-btn {
    background: none;
    border: none;
    padding: 0.5rem 1rem;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-light);
    border-bottom: 2px solid transparent;
    cursor: pointer;
    transition: all 0.2s;
}

.tab-nav-btn.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
}

/* Distance Converter */
.distance-converter-section {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 1rem;
    box-shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    margin-bottom: 1.5rem;
}

.distance-inputs-simple {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.dist-input-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    flex: 1;
}

.dist-input {
    width: 100%;
    max-width: 120px;
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--primary);
    text-align: center;
    border: none;
    background: transparent;
    padding: 0;
    -moz-appearance: textfield;
}

.dist-input-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    background: var(--surface-bg);
    padding: 1rem 0.5rem;
    border-radius: 1rem;
    box-sizing: border-box;
}

.dist-input:focus {
    outline: none;
}

.dist-label {
    font-size: 0.9rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-light);
    margin-top: 0.5rem;
}

.dist-equals {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-lighter);
    margin-top: -1rem; /* slightly adjust up to align with inputs visually */
}

/* Theme Button styles */
.theme-btn {
    position: absolute;
    top: 50%;
    right: 0;
    transform: translateY(-50%);
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    color: var(--text-light);
    display: flex;
    align-items: center;
    justify-content: center;
}
.theme-btn:hover {
    background: var(--surface-bg);
}

#tab-distance .race-grid {
    grid-template-columns: 1fr;
}

#tab-distance .race-item {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    text-align: right;
    gap: 0.5rem;
}

#tab-distance .race-item span:first-child {
    text-align: left;
}

#tab-distance .race-item.header {
    font-size: 0.9rem;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    border-bottom: 2px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.distance-row {
    cursor: pointer;
    transition: background-color 0.1s, transform 0.1s;
    border-radius: 0.5rem;
    padding: 0.75rem 0.5rem;
    margin: -0.75rem -0.5rem; /* Offset padding */
}

.distance-row:active {
    background-color: var(--surface-bg);
    transform: scale(0.98);
}

.less-common {
    display: none !important;
}

.show-all .less-common {
    display: grid !important;
}

/* Utilities */
.hidden {
    display: none !important;
}
.full-width {
    width: 100%;
}
.mt-1 {
    margin-top: 1rem;
}
.surface-bg {
    background-color: var(--surface-bg);
}

/* Toast */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--text-main);
    color: var(--bg-color);
    padding: 0.75rem 1.5rem;
    border-radius: 2rem;
    display: flex;
    align-items: center;
    gap: 1rem;
    box-shadow: 0 10px 15px -3px rgb(0 0 0 / 0.3);
    z-index: 1000;
    font-weight: 500;
}

.toast-btn {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 1rem;
    font-weight: 600;
    cursor: pointer;
}