/* CSS Custom Properties for Theming */
:root {
    --bg-primary: #FFFFFF;
    --bg-secondary: #F9FAFB;
    --border-color: #E5E7EB;
    --text-primary: #111827;
    --text-secondary: #6B7280;
    --primary: #3B82F6;
    --primary-hover: #2563EB;
    --success: #10B981;
    --error: #EF4444;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 6px rgba(0, 0, 0, 0.1);
    --radius: 8px;
    --transition: 0.2s ease;
}

[data-theme="dark"] {
    --bg-primary: #111827;
    --bg-secondary: #1F2937;
    --border-color: #374151;
    --text-primary: #F9FAFB;
    --text-secondary: #9CA3AF;
    --primary: #60A5FA;
    --primary-hover: #3B82F6;
    --success: #34D399;
    --error: #F87171;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 4px 6px rgba(0, 0, 0, 0.3);
}

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

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

/* Container */
.container {
    max-width: 700px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

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

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

h1 {
    font-size: 1.75rem;
    font-weight: 700;
}

.tagline {
    color: var(--text-secondary);
    font-size: 1rem;
    margin-bottom: 0.5rem;
}

.timezone-display {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Icon Button */
.icon-btn {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 0.5rem;
    cursor: pointer;
    font-size: 1.25rem;
    line-height: 1;
    transition: background-color var(--transition), border-color var(--transition);
}

.icon-btn:hover {
    background: var(--border-color);
}

.sun-icon {
    display: none;
}

.moon-icon {
    display: inline;
}

[data-theme="dark"] .sun-icon {
    display: inline;
}

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

/* Sections */
section {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: var(--shadow);
}

h2 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Input Section */
.input-section label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.input-row {
    display: flex;
    gap: 0.5rem;
}

#timestamp-input {
    flex: 1;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: border-color var(--transition), box-shadow var(--transition);
}

#timestamp-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

#timestamp-input::placeholder {
    color: var(--text-secondary);
}

/* Buttons */
.btn {
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
    font-weight: 500;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    transition: background-color var(--transition), transform var(--transition);
    white-space: nowrap;
}

.btn:active {
    transform: scale(0.98);
}

.btn-primary {
    background: var(--primary);
    color: white;
}

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

.btn-secondary {
    background: var(--border-color);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background: var(--text-secondary);
    color: white;
}

/* Presets Row */
.presets-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 0.75rem;
    align-items: center;
}

.presets-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.preset-btn {
    padding: 0.25rem 0.5rem;
    font-size: 0.75rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    color: var(--text-secondary);
    cursor: pointer;
    transition: background-color var(--transition), border-color var(--transition), color var(--transition);
}

.preset-btn:hover {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

/* Detected Format */
.detected-format {
    margin-top: 0.75rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
    min-height: 1.4em;
}

.detected-format.success {
    color: var(--success);
}

.detected-format.error {
    color: var(--error);
}

/* Results Header */
.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.results-header h2 {
    margin-bottom: 0;
}

.results-actions {
    display: flex;
    gap: 0.5rem;
}

.btn-small {
    padding: 0.375rem 0.75rem;
    font-size: 0.75rem;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.btn-small:hover {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

.click-hint {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    font-style: italic;
}

/* Results Grid */
.results-grid {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.result-row {
    display: grid;
    grid-template-columns: 140px 1fr auto;
    gap: 0.75rem;
    align-items: center;
    padding: 0.5rem;
    background: var(--bg-primary);
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
}

.result-label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.result-value {
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    font-size: 0.875rem;
    word-break: break-all;
    color: var(--text-primary);
}

.result-value.clickable {
    cursor: pointer;
    padding: 0.25rem 0.5rem;
    margin: -0.25rem -0.5rem;
    border-radius: 4px;
    transition: background-color var(--transition), color var(--transition);
}

.result-value.clickable:hover {
    background: var(--primary);
    color: white;
}

.result-value.clickable:focus {
    outline: none;
    background: var(--primary);
    color: white;
}

/* Copy Button */
.copy-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 0.4rem 0.6rem;
    cursor: pointer;
    transition: background-color var(--transition), border-color var(--transition);
    font-size: 1rem;
    line-height: 1;
}

.copy-btn:hover {
    background: var(--border-color);
}

.copy-btn.copied {
    background: var(--success);
    border-color: var(--success);
    color: white;
}

/* Timezone Section */
.timezone-row {
    margin-bottom: 1rem;
}

/* Custom Select Dropdown */
.custom-select {
    position: relative;
    width: 100%;
}

.select-trigger {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--bg-primary);
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    text-align: left;
    transition: border-color var(--transition), box-shadow var(--transition);
}

.select-trigger:hover {
    border-color: var(--text-secondary);
}

.select-trigger:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.select-trigger[aria-expanded="true"] {
    border-color: var(--primary);
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
}

.select-value {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    flex: 1;
}

.select-arrow {
    margin-left: 0.5rem;
    transition: transform var(--transition);
}

.select-trigger[aria-expanded="true"] .select-arrow {
    transform: rotate(180deg);
}

.select-dropdown {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border: 1px solid var(--primary);
    border-top: none;
    border-bottom-left-radius: var(--radius);
    border-bottom-right-radius: var(--radius);
    max-height: 300px;
    overflow-y: auto;
    overscroll-behavior: contain;
    z-index: 100;
    display: none;
    box-shadow: var(--shadow-lg);
}

.select-search {
    position: sticky;
    top: 0;
    background: var(--bg-primary);
    padding: 0.5rem;
    border-bottom: 1px solid var(--border-color);
}

.select-search input {
    width: 100%;
    padding: 0.5rem 0.75rem;
    font-size: 0.875rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--bg-secondary);
    color: var(--text-primary);
}

.select-search input:focus {
    outline: none;
    border-color: var(--primary);
}

.select-search input::placeholder {
    color: var(--text-secondary);
}

.select-option.hidden {
    display: none;
}

.select-dropdown.open {
    display: block;
}

.select-option {
    padding: 0.75rem 1rem;
    cursor: pointer;
    transition: background-color var(--transition);
    border-bottom: 1px solid var(--border-color);
}

.select-option:last-child {
    border-bottom: none;
}

.select-option:hover,
.select-option:focus {
    background: var(--bg-secondary);
    outline: none;
}

.select-option.selected {
    background: var(--primary);
    color: white;
}

.select-option.selected:hover {
    background: var(--primary-hover);
}

/* Scrollbar styling for dropdown */
.select-dropdown::-webkit-scrollbar {
    width: 8px;
}

.select-dropdown::-webkit-scrollbar-track {
    background: var(--bg-secondary);
    border-radius: 4px;
}

.select-dropdown::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

.select-dropdown::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Section Hint */
.section-hint {
    font-size: 0.8125rem;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

/* Date Math Section */
.date-math-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

.math-input-group {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.math-input-group label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.math-input-row {
    display: flex;
    gap: 0.25rem;
}

.math-input-row input {
    flex: 1;
    width: 100%;
    padding: 0.5rem;
    font-size: 0.875rem;
    text-align: center;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--bg-primary);
    color: var(--text-primary);
}

.math-input-row input:focus {
    outline: none;
    border-color: var(--primary);
}

.math-btn {
    padding: 0.5rem 0.75rem;
    font-size: 1rem;
    font-weight: 600;
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    cursor: pointer;
    transition: background-color var(--transition), border-color var(--transition);
    color: var(--text-primary);
}

.math-btn:hover {
    background: var(--primary);
    border-color: var(--primary);
    color: white;
}

.math-result {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.math-result .result-row {
    margin-bottom: 0.75rem;
}

#use-math-result {
    margin-top: 0.5rem;
}

/* Duration Calculator Section */
.duration-inputs {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.duration-input-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.duration-input-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.duration-input-row {
    display: flex;
    gap: 0.5rem;
}

.duration-input-row input {
    flex: 1;
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--bg-primary);
    color: var(--text-primary);
}

.duration-input-row input:focus {
    outline: none;
    border-color: var(--primary);
}

.duration-detected {
    font-size: 0.75rem;
    color: var(--success);
    min-height: 1.2em;
}

.duration-detected.error {
    color: var(--error);
}

.duration-result {
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.duration-result-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

.duration-stat {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1rem;
    text-align: center;
}

.duration-stat-value {
    display: block;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary);
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    word-break: break-all;
}

.duration-stat-label {
    display: block;
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

/* Bulk Conversion Section */
#bulk-input {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 0.875rem;
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--bg-primary);
    color: var(--text-primary);
    resize: vertical;
    min-height: 100px;
}

#bulk-input:focus {
    outline: none;
    border-color: var(--primary);
}

#bulk-input::placeholder {
    color: var(--text-secondary);
}

.bulk-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.75rem;
}

.bulk-results {
    margin-top: 1rem;
    overflow-x: auto;
}

.bulk-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.8125rem;
}

.bulk-table th,
.bulk-table td {
    padding: 0.75rem 0.5rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.bulk-table th {
    font-weight: 600;
    color: var(--text-secondary);
    background: var(--bg-primary);
    position: sticky;
    top: 0;
}

.bulk-table td {
    font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
    word-break: break-all;
}

.bulk-table tr:hover td {
    background: var(--bg-primary);
}

.bulk-table .error-row td {
    color: var(--error);
}

/* Footer */
footer {
    text-align: center;
    padding-top: 1rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

footer p {
    margin-bottom: 0.5rem;
}

.footer-link {
    color: var(--primary);
    text-decoration: none;
}

.footer-link:hover {
    text-decoration: underline;
}

.sister-site {
    margin-top: 0.75rem;
    padding-top: 0.75rem;
    border-top: 1px solid var(--border-color);
    font-size: 0.8125rem;
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text-primary);
    color: var(--bg-primary);
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius);
    font-size: 0.875rem;
    font-weight: 500;
    opacity: 0;
    transition: transform 0.3s ease, opacity 0.3s ease;
    z-index: 1000;
    box-shadow: var(--shadow-lg);
}

.toast.show {
    transform: translateX(-50%) translateY(0);
    opacity: 1;
}

.toast.success {
    background: var(--success);
    color: white;
}

.toast.error {
    background: var(--error);
    color: white;
}

/* Mobile Responsive */
@media (max-width: 600px) {
    .container {
        padding: 1rem;
    }

    h1 {
        font-size: 1.5rem;
    }

    .input-row {
        flex-wrap: wrap;
    }

    #timestamp-input {
        width: 100%;
        flex: none;
    }

    .btn {
        flex: 1;
    }

    .presets-row {
        margin-top: 0.5rem;
    }

    .presets-label {
        width: 100%;
        margin-bottom: 0.25rem;
    }

    .results-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .results-actions {
        width: 100%;
    }

    .results-actions .btn-small {
        flex: 1;
    }

    .result-row {
        grid-template-columns: 1fr auto;
        gap: 0.5rem;
    }

    .result-label {
        grid-column: 1 / -1;
        margin-bottom: -0.25rem;
    }

    section {
        padding: 1rem;
    }

    /* Date Math responsive */
    .date-math-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    /* Duration responsive */
    .duration-inputs {
        grid-template-columns: 1fr;
    }

    .duration-result-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    /* Bulk responsive */
    .bulk-actions {
        flex-wrap: wrap;
    }

    .bulk-actions .btn {
        flex: 1 1 auto;
    }

}

/* Focus visible for accessibility */
:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Reduced motion preference */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        transition-duration: 0.01ms !important;
    }
}