:root {
    --primary: #e65100;
    --primary-light: #ff833a;
    --primary-dark: #ac1900;
    --secondary: #1565c0;
    --secondary-light: #5e92f3;
    --bg: #fafafa;
    --card-bg: #ffffff;
    --text: #212121;
    --text-light: #757575;
    --success: #2e7d32;
    --danger: #c62828;
    --border: #e0e0e0;
    --radius: 12px;
    --shadow: 0 2px 8px rgba(0,0,0,0.1);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.15);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    -webkit-tap-highlight-color: transparent;
}

/* --- Navbar --- */
.navbar {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    padding: 0 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
    min-height: 52px;
    gap: 8px;
}

.nav-left {
    display: flex;
    align-items: center;
    gap: 4px;
    min-width: 0;
}

.nav-brand {
    color: white;
    text-decoration: none;
    font-size: 1.1rem;
    font-weight: 700;
    white-space: nowrap;
}

.nav-back {
    display: flex;
    align-items: center;
    justify-content: center;
    color: rgba(255,255,255,0.85);
    text-decoration: none;
    font-size: 1.4rem;
    width: 36px;
    height: 36px;
    border-radius: 8px;
    flex-shrink: 0;
    transition: background 0.15s;
}

.nav-back:hover {
    background: rgba(255,255,255,0.15);
}

.nav-right {
    display: flex;
    align-items: center;
    gap: 6px;
    flex-shrink: 0;
}

.nav-link {
    color: rgba(255,255,255,0.85);
    text-decoration: none;
    font-size: 0.82rem;
    padding: 6px 10px;
    border-radius: 6px;
    transition: background 0.15s;
    white-space: nowrap;
}

.nav-link:hover {
    background: rgba(255,255,255,0.15);
    color: white;
}

.nav-version {
    font-size: 0.65rem;
    font-weight: 400;
    opacity: 0.5;
    vertical-align: middle;
}

.nav-link-dim {
    opacity: 0.6;
}

.nav-user {
    font-size: 0.82rem;
    opacity: 0.7;
    white-space: nowrap;
    max-width: 80px;
    overflow: hidden;
    text-overflow: ellipsis;
}

.sync-dot {
    display: inline-block;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    margin-right: 4px;
    vertical-align: middle;
    background: rgba(255,255,255,0.3);
}

.sync-dot.synced { background: #66bb6a; }
.sync-dot.syncing { background: #ffa726; }
.sync-dot.offline { background: #ef5350; }

.nav-dropdown-sync {
    padding: 8px 16px;
    font-size: 0.8rem;
    color: var(--text-light);
}

.nav-dropdown {
    position: relative;
}

.nav-dropdown-toggle {
    background: none;
    border: none;
    cursor: pointer;
    font-family: inherit;
}

.nav-dropdown-menu {
    display: none;
    position: absolute;
    right: 0;
    top: calc(100% + 6px);
    background: white;
    border-radius: 10px;
    box-shadow: var(--shadow-lg);
    min-width: 160px;
    z-index: 200;
    overflow: hidden;
}

.nav-dropdown-menu.open {
    display: block;
}

.nav-dropdown-menu a {
    display: block;
    padding: 10px 16px;
    color: var(--text);
    text-decoration: none;
    font-size: 0.88rem;
    transition: background 0.12s;
}

.nav-dropdown-menu a:hover {
    background: #f5f5f5;
}

.nav-dropdown-sep {
    height: 1px;
    background: var(--border);
    margin: 4px 0;
}

/* --- Page header (below navbar) --- */
.page-header {
    padding: 16px 16px 0;
    max-width: 1200px;
    margin: 0 auto;
}

.page-header h1 {
    font-size: 1.3rem;
    font-weight: 700;
}

.page-header-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
}

/* --- Legacy header (kept for transition) --- */
.header {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    padding: 16px 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
}

.header h1 {
    font-size: 1.2rem;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 8px;
}

.header-actions {
    display: flex;
    gap: 12px;
    align-items: center;
}

.header a, .header button {
    color: rgba(255,255,255,0.9);
    text-decoration: none;
    font-size: 0.85rem;
    background: none;
    border: none;
    cursor: pointer;
}

.header a:hover, .header button:hover {
    color: white;
}

/* --- Container --- */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px 16px;
}

/* --- Cards --- */
.card {
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 20px;
    margin-bottom: 16px;
}

/* --- Forms --- */
.form-group {
    margin-bottom: 16px;
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-light);
    margin-bottom: 6px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
    outline: none;
}

.form-group input:focus {
    border-color: var(--primary);
}

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
    -webkit-user-select: none;
    user-select: none;
}

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

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

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

.btn-secondary:hover {
    background: #0d47a1;
}

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

.btn-success:hover {
    background: #1b5e20;
}

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

.btn-danger:hover {
    background: #b71c1c;
}

.btn-outline {
    background: transparent;
    color: var(--text);
    border: 2px solid var(--border);
}

.btn-outline:hover {
    border-color: var(--text-light);
}

.btn-block {
    width: 100%;
}

.btn-sm {
    padding: 8px 14px;
    font-size: 0.85rem;
}

.btn-lg {
    padding: 16px 32px;
    font-size: 1.1rem;
}

/* --- Flash messages --- */
.flash {
    padding: 12px 16px;
    border-radius: 8px;
    margin-bottom: 16px;
    font-size: 0.9rem;
    font-weight: 500;
}

.flash-error {
    background: #ffebee;
    color: var(--danger);
    border: 1px solid #ef9a9a;
}

.flash-success {
    background: #e8f5e9;
    color: var(--success);
    border: 1px solid #a5d6a7;
}

/* --- Auth pages --- */
.auth-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, #fff3e0, #ffe0b2);
}

.auth-logo {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary);
    margin-bottom: 8px;
}

.auth-subtitle {
    color: var(--text-light);
    margin-bottom: 32px;
    font-size: 0.95rem;
}

.auth-card {
    background: white;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
    padding: 32px 24px;
    width: 100%;
    max-width: 400px;
}

.auth-card h2 {
    text-align: center;
    margin-bottom: 24px;
    font-size: 1.3rem;
}

.auth-link {
    text-align: center;
    margin-top: 20px;
    font-size: 0.9rem;
    color: var(--text-light);
}

.auth-link a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
}

/* --- Dashboard set list --- */
.set-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-bottom: 12px;
    text-decoration: none;
    color: var(--text);
    transition: transform 0.15s, box-shadow 0.15s;
}

.set-item:active {
    transform: scale(0.98);
}

.set-info h3 {
    font-size: 1.05rem;
    margin-bottom: 4px;
}

.set-info span {
    font-size: 0.8rem;
    color: var(--text-light);
}

.set-arrow {
    color: var(--text-light);
    font-size: 1.2rem;
}

.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-light);
}

.empty-state p {
    margin-bottom: 20px;
    font-size: 1.1rem;
}

/* --- Word list --- */
.word-row {
    display: flex;
    align-items: center;
    padding: 12px 0;
    border-bottom: 1px solid var(--border);
    gap: 12px;
}

.word-row:last-child {
    border-bottom: none;
}

.word-texts {
    flex: 1;
    display: flex;
    gap: 8px;
    align-items: baseline;
    min-width: 0;
}

.word-czech {
    font-weight: 600;
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.word-sep {
    color: var(--text-light);
    flex-shrink: 0;
}

.word-spanish {
    color: var(--primary);
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.word-stat {
    font-size: 0.65rem;
    font-weight: 700;
    padding: 1px 5px;
    border-radius: 4px;
    flex-shrink: 0;
    margin-left: 4px;
}
.stat-bad { background: #ffebee; color: var(--danger); }
.stat-med { background: #fff3e0; color: #e65100; }
.stat-ok { background: #e8f5e9; color: var(--success);
}

.word-actions {
    display: flex;
    gap: 6px;
    flex-shrink: 0;
}

.btn-speak {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 0.85rem;
    padding: 2px;
    opacity: 0.4;
    flex-shrink: 0;
    transition: opacity 0.15s;
}

.btn-speak:hover, .btn-speak:active {
    opacity: 1;
}

.btn-speak-toggle {
    background: none;
    border: 2px solid var(--border);
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    padding: 4px 8px;
    opacity: 0.4;
    transition: all 0.15s;
}

.btn-speak-toggle.active {
    opacity: 1;
    border-color: var(--primary);
    background: #fff3e0;
}

.word-actions button, .word-actions .btn-icon {
    background: none;
    border: none;
    cursor: pointer;
    padding: 6px;
    border-radius: 6px;
    color: var(--text-light);
    font-size: 1rem;
    transition: background 0.15s;
}

.word-actions button:hover, .word-actions .btn-icon:hover {
    background: #f5f5f5;
}

/* --- Add word form --- */
.add-word-form {
    display: flex;
    gap: 8px;
    padding-top: 12px;
    flex-wrap: wrap;
}

.add-word-form input {
    flex: 1;
    min-width: 100px;
    padding: 10px 14px;
    border: 2px solid var(--border);
    border-radius: 8px;
    font-size: 0.95rem;
    outline: none;
    transition: border-color 0.2s;
}

.add-word-form input:focus {
    border-color: var(--primary);
}

.add-word-form button {
    flex-shrink: 0;
}

/* --- Practice --- */
.practice-header {
    text-align: center;
    margin-bottom: 20px;
}

.practice-progress {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 8px;
}

.progress-bar {
    width: 100%;
    height: 6px;
    background: var(--border);
    border-radius: 3px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--primary);
    border-radius: 3px;
    transition: width 0.3s ease;
}

.flashcard-container {
    perspective: 1000px;
    margin: 20px 0;
}

.flashcard {
    position: relative;
    width: 100%;
    min-height: 220px;
    cursor: pointer;
    -webkit-user-select: none;
    user-select: none;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    min-height: 220px;
    transition: transform 0.5s;
    transform-style: preserve-3d;
}

.flashcard.flipped .flashcard-inner {
    transform: rotateY(180deg);
}

.flashcard-front, .flashcard-back {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 30px 20px;
    border-radius: 16px;
    box-shadow: var(--shadow-lg);
}

.flashcard-front {
    background: linear-gradient(135deg, #fff, #f5f5f5);
}

.flashcard-back {
    background: linear-gradient(135deg, #fff3e0, #ffe0b2);
    transform: rotateY(180deg);
}

.flashcard-lang {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-light);
    margin-bottom: 12px;
    font-weight: 600;
}

.flashcard-word {
    font-size: 1.8rem;
    font-weight: 700;
    text-align: center;
    line-height: 1.3;
}

.flashcard-hint {
    font-size: 0.8rem;
    color: var(--text-light);
    margin-top: 16px;
}

.practice-ranges {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 10px;
}

.practice-range-btn {
    min-width: 70px;
}

.practice-buttons {
    display: flex;
    gap: 12px;
    margin-top: 16px;
}

.practice-buttons .btn {
    flex: 1;
    padding: 16px;
    font-size: 1.05rem;
}

.practice-done {
    text-align: center;
    padding: 40px 20px;
}

.practice-done h2 {
    font-size: 1.5rem;
    margin-bottom: 12px;
}

.practice-done p {
    color: var(--text-light);
    margin-bottom: 24px;
}

.practice-stats {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 30px;
}

.stat {
    text-align: center;
}

.stat-number {
    font-size: 2rem;
    font-weight: 800;
}

.stat-number.good { color: var(--success); }
.stat-number.bad { color: var(--danger); }

.stat-label {
    font-size: 0.8rem;
    color: var(--text-light);
    text-transform: uppercase;
}

/* --- Direction picker --- */
.direction-picker {
    display: flex;
    gap: 8px;
    margin-bottom: 20px;
}

.direction-btn {
    flex: 1;
    padding: 12px;
    border: 2px solid var(--border);
    border-radius: 8px;
    background: white;
    cursor: pointer;
    text-align: center;
    font-size: 0.85rem;
    font-weight: 600;
    transition: all 0.2s;
}

.direction-btn.active {
    border-color: var(--primary);
    background: #fff3e0;
    color: var(--primary);
}

/* --- Back link --- */
.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: var(--text-light);
    text-decoration: none;
    font-size: 0.9rem;
    margin-bottom: 16px;
}

.back-link:hover {
    color: var(--text);
}

/* --- Section header --- */
.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.section-header h2 {
    font-size: 1.2rem;
}

/* --- Edit word modal --- */
.modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: 200;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.modal-overlay.active {
    display: flex;
}

.modal {
    background: white;
    border-radius: 16px;
    padding: 24px;
    width: 100%;
    max-width: 400px;
    box-shadow: var(--shadow-lg);
}

.modal h3 {
    margin-bottom: 16px;
}

.modal-actions {
    display: flex;
    gap: 8px;
    margin-top: 16px;
    justify-content: flex-end;
}

/* --- Responsive --- */
@media (max-width: 400px) {
    .add-word-form {
        flex-direction: column;
    }

    .add-word-form input {
        min-width: unset;
    }

    .flashcard-word {
        font-size: 1.5rem;
    }

    .practice-buttons .btn {
        padding: 14px 8px;
        font-size: 0.95rem;
    }
}