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

:root {
    --primary-color: #0052cc;
    --primary-hover: #0747a6;
    --secondary-color: #42526e;
    --background: #ffffff;
    --surface: #f4f5f7;
    --surface-hover: #ebecf0;
    --text-primary: #172b4d;
    --text-secondary: #6b778c;
    --border: #dfe1e6;
    --success: #00875a;
    --error: #de350b;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 40px rgba(0,0,0,0.08);
    --radius: 8px;
    --radius-sm: 4px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: var(--text-primary);
    line-height: 1.6;
    padding: 20px;
}

.container {
    max-width: 960px;
    margin: 0 auto;
    background: var(--background);
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

header {
    background: linear-gradient(135deg, var(--primary-color) 0%, #0747a6 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.95;
    margin-bottom: 20px;
}

.lang-selector {
    display: flex;
    gap: 10px;
    justify-content: center;
    margin-top: 20px;
}

.lang-btn {
    padding: 8px 16px;
    background: rgba(255,255,255,0.2);
    color: white;
    border: 1px solid rgba(255,255,255,0.3);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.9rem;
    font-weight: 500;
}

.lang-btn:hover {
    background: rgba(255,255,255,0.3);
    transform: translateY(-1px);
}

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

main {
    padding: 30px;
}

h2 {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--border);
}

/* Cron output */
.cron-output-section {
    background: var(--surface);
    padding: 25px;
    border-radius: var(--radius);
    margin-bottom: 30px;
}

.cron-display {
    display: flex;
    gap: 10px;
    align-items: center;
    margin-top: 15px;
}

.cron-input-field {
    flex: 1;
    padding: 14px 18px;
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', monospace;
    font-size: 1.3rem;
    font-weight: 600;
    text-align: center;
    letter-spacing: 2px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    background: white;
    color: var(--text-primary);
    transition: border-color 0.3s;
}

.cron-input-field:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0,82,204,0.1);
}

.cron-description {
    margin-top: 12px;
    padding: 12px 16px;
    background: white;
    border-radius: var(--radius-sm);
    color: var(--secondary-color);
    font-size: 1.05rem;
    line-height: 1.5;
    min-height: 44px;
    display: flex;
    align-items: center;
}

.cron-error {
    margin-top: 8px;
    color: var(--error);
    font-size: 0.9rem;
    display: none;
}

.cron-error.visible {
    display: block;
}

.btn-primary {
    padding: 12px 24px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.copy-btn {
    padding: 10px 14px;
    background: white;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 1.1rem;
}

.copy-btn:hover {
    background: var(--surface-hover);
    transform: scale(1.05);
}

/* Preset bar */
.preset-bar {
    display: flex;
    gap: 8px;
    align-items: center;
    flex-wrap: wrap;
    margin-bottom: 20px;
}

.preset-label {
    font-weight: 600;
    color: var(--text-secondary);
    margin-right: 4px;
}

.preset-btn {
    padding: 6px 14px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.85rem;
    color: var(--text-primary);
    transition: all 0.2s;
}

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

/* Builder fields */
.builder-section {
    margin-bottom: 30px;
}

.fields-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
    gap: 16px;
}

.field-card {
    background: white;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    transition: box-shadow 0.2s;
}

.field-card:hover {
    box-shadow: var(--shadow-sm);
}

.field-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.field-label {
    font-weight: 700;
    font-size: 1rem;
    color: var(--text-primary);
}

.field-range {
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', monospace;
    font-size: 0.8rem;
    color: var(--text-secondary);
    background: var(--surface);
    padding: 2px 8px;
    border-radius: var(--radius-sm);
}

.field-type-select {
    width: 100%;
    padding: 8px 10px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    background: white;
    cursor: pointer;
    margin-bottom: 10px;
    transition: border-color 0.3s;
}

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

.field-config {
    min-height: 36px;
}

.field-config input,
.field-config select {
    width: 100%;
    padding: 6px 8px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 0.85rem;
    margin-bottom: 6px;
}

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

.field-config .range-inputs {
    display: flex;
    gap: 6px;
    align-items: center;
}

.field-config .range-inputs input {
    width: 50%;
}

.field-config .range-sep {
    color: var(--text-secondary);
    font-weight: 600;
}

.toggle-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
}

.toggle-btn {
    width: 32px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: white;
    cursor: pointer;
    font-size: 0.75rem;
    color: var(--text-primary);
    transition: all 0.15s;
}

.toggle-btn:hover {
    border-color: var(--primary-color);
}

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

.dow-toggle-btn {
    width: auto;
    min-width: 36px;
    padding: 0 6px;
}

/* Next runs */
.schedule-section {
    background: white;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 25px;
    margin-bottom: 30px;
}

.next-runs-list {
    display: grid;
    gap: 8px;
}

.next-run-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 14px;
    background: var(--surface);
    border-radius: var(--radius-sm);
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', monospace;
    font-size: 0.9rem;
}

.next-run-index {
    font-weight: 700;
    color: var(--primary-color);
    min-width: 24px;
}

.next-run-date {
    color: var(--text-primary);
}

.next-run-relative {
    margin-left: auto;
    color: var(--text-secondary);
    font-size: 0.8rem;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

/* Reference */
.reference-section {
    margin-bottom: 30px;
}

.reference-table-wrap {
    overflow-x: auto;
}

.reference-table {
    width: 100%;
    border-collapse: collapse;
}

.reference-table th,
.reference-table td {
    padding: 10px 14px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

.reference-table th {
    background: var(--surface);
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.reference-table td.mono {
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', monospace;
}

.mono {
    font-family: 'SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', monospace;
}

/* Toast */
.toast {
    position: fixed;
    bottom: 30px;
    right: 30px;
    padding: 12px 20px;
    background: var(--success);
    color: white;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-md);
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.3s ease;
    z-index: 1000;
    font-weight: 500;
}

.toast.show {
    opacity: 1;
    transform: translateY(0);
}

footer {
    text-align: center;
    padding: 20px;
    color: var(--text-secondary);
    background: var(--surface);
    border-top: 1px solid var(--border);
}

@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    h1 {
        font-size: 2rem;
    }

    .fields-grid {
        grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
    }

    .cron-input-field {
        font-size: 1.1rem;
    }

    .next-run-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 4px;
    }

    .next-run-relative {
        margin-left: 0;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.5rem;
    }

    .subtitle {
        font-size: 0.95rem;
    }

    main {
        padding: 20px;
    }

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

    .cron-display {
        flex-wrap: wrap;
    }

    .cron-input-field {
        width: 100%;
    }

    .preset-bar {
        justify-content: center;
    }
}