/* Design Tokens */
:root {
    /* Dark Theme (Default) */
    --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e1b4b 100%);
    --card-bg: rgba(30, 41, 59, 0.7);
    --card-border: rgba(255, 255, 255, 0.08);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --primary-glow: rgba(99, 102, 241, 0.35);
    --accent: #f43f5e;
    --accent-glow: rgba(244, 63, 94, 0.3);
    --success: #10b981;
    --panel-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
    
    /* Font definitions */
    --font-display: 'Outfit', 'Inter', system-ui, sans-serif;
    --font-body: 'Inter', 'Nanum Gothic', system-ui, sans-serif;
    
    /* Animation Speeds */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
}

body.light-theme {
    /* Light Theme */
    --bg-gradient: linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 100%);
    --card-bg: rgba(255, 255, 255, 0.8);
    --card-border: rgba(0, 0, 0, 0.06);
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --primary-glow: rgba(79, 70, 229, 0.15);
    --accent: #e11d48;
    --accent-glow: rgba(225, 29, 72, 0.15);
    --panel-shadow: 0 8px 32px 0 rgba(148, 163, 184, 0.18);
}

/* Reset and Core Styles */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-body);
    background: var(--bg-gradient);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 2rem 1rem;
    transition: background var(--transition-normal);
    line-height: 1.5;
}

/* Scrollbars */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--text-muted);
    border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Layout Container */
.app-container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
}

/* Glassmorphism Cards */
.card {
    background: var(--card-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--card-border);
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: var(--panel-shadow);
    transition: transform var(--transition-fast), border-color var(--transition-fast);
}

/* Header */
.app-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding: 0 0.5rem;
}

.logo-area {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon {
    font-size: 2rem;
    filter: drop-shadow(0 0 8px var(--primary-glow));
}

.logo-area h1 {
    font-family: var(--font-display);
    font-weight: 800;
    font-size: 1.75rem;
    letter-spacing: -0.5px;
    background: linear-gradient(to right, #818cf8, #f43f5e);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* Streak Badge */
.streak-badge {
    background: rgba(244, 63, 94, 0.1);
    border: 1px solid rgba(244, 63, 94, 0.2);
    color: var(--accent);
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 0.95rem;
    padding: 0.5rem 1rem;
    border-radius: 50px;
    display: flex;
    align-items: center;
    gap: 0.4rem;
    box-shadow: 0 0 10px var(--accent-glow);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.03); }
}

/* Theme Toggle Button */
.icon-btn {
    background: var(--card-bg);
    border: 1px solid var(--card-border);
    color: var(--text-primary);
    width: 42px;
    height: 42px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.icon-btn:hover {
    transform: translateY(-2px);
    border-color: var(--primary);
    box-shadow: 0 0 12px var(--primary-glow);
}

.sun-icon { display: none; }
.moon-icon { display: block; }
body.light-theme .sun-icon { display: block; }
body.light-theme .moon-icon { display: none; }

/* Main Grid Layout */
.main-layout {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 1.5rem;
}

@media (max-width: 900px) {
    .main-layout {
        grid-template-columns: 1fr;
    }
}

/* Writing Area */
.writing-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.section-header h2 {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.35rem;
}

.date-picker {
    background: rgba(0, 0, 0, 0.15);
    border: 1px solid var(--card-border);
    color: var(--text-primary);
    padding: 0.5rem 0.75rem;
    border-radius: 8px;
    font-family: var(--font-display);
    font-weight: 500;
    outline: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.date-picker:focus {
    border-color: var(--primary);
}

/* Mood Selector */
.mood-container {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.label-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.mood-selector {
    display: flex;
    justify-content: space-between;
    gap: 0.5rem;
}

.mood-btn {
    flex: 1;
    background: rgba(0, 0, 0, 0.1);
    border: 1px solid var(--card-border);
    border-radius: 12px;
    padding: 0.75rem 0.5rem;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
    transition: all var(--transition-fast);
}

.mood-btn .emoji {
    font-size: 1.6rem;
    transition: transform var(--transition-fast);
}

.mood-btn .mood-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 600;
}

.mood-btn:hover {
    background: rgba(255, 255, 255, 0.05);
    transform: translateY(-2px);
}

.mood-btn:hover .emoji {
    transform: scale(1.2);
}

.mood-btn.selected {
    background: rgba(99, 102, 241, 0.15);
    border-color: var(--primary);
    box-shadow: 0 0 12px var(--primary-glow);
}

.mood-btn.selected .mood-label {
    color: var(--text-primary);
}

/* Form Styles */
.diary-form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

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

.input-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.sentence-input-group label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.word-counter {
    font-size: 0.75rem;
    font-family: var(--font-display);
    color: var(--text-muted);
}

.sentence-input-group textarea {
    background: rgba(0, 0, 0, 0.15);
    border: 1px solid var(--card-border);
    color: var(--text-primary);
    border-radius: 10px;
    padding: 0.85rem 1rem;
    font-size: 0.95rem;
    font-family: var(--font-body);
    resize: none;
    height: 70px;
    outline: none;
    transition: all var(--transition-fast);
}

.sentence-input-group textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 8px var(--primary-glow);
    background: rgba(0, 0, 0, 0.25);
}

/* Form actions & Tips */
.form-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    margin-top: 0.5rem;
    flex-wrap: wrap;
}

.writing-tips {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(255, 255, 255, 0.04);
    padding: 0.5rem 0.75rem;
    border-radius: 8px;
    max-width: 60%;
}

.tip-badge {
    background: var(--primary);
    color: #fff;
    font-size: 0.7rem;
    font-weight: 700;
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    text-transform: uppercase;
}

.tip-text {
    font-size: 0.8rem;
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
    border: none;
    border-radius: 10px;
    padding: 0.75rem 1.5rem;
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 0.95rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all var(--transition-fast);
    box-shadow: 0 4px 14px var(--primary-glow);
}

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px var(--primary-glow);
}

/* Dashboard & Stats */
.dashboard-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

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

.stat-card {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-icon {
    font-size: 2rem;
}

.stat-info {
    display: flex;
    flex-direction: column;
}

.stat-value {
    font-family: var(--font-display);
    font-size: 1.6rem;
    font-weight: 800;
    line-height: 1;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 500;
    margin-top: 0.25rem;
}

/* Archive Box */
.archive-card {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
    max-height: 520px;
}

.archive-header {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.archive-header h3 {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.15rem;
}

.archive-controls {
    display: flex;
    gap: 0.5rem;
}

.search-input {
    flex: 1;
    background: rgba(0, 0, 0, 0.15);
    border: 1px solid var(--card-border);
    color: var(--text-primary);
    border-radius: 8px;
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
    outline: none;
    transition: all var(--transition-fast);
}

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

.filter-select {
    background: rgba(0, 0, 0, 0.15);
    border: 1px solid var(--card-border);
    color: var(--text-primary);
    border-radius: 8px;
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
    outline: none;
    cursor: pointer;
}

/* Diary List */
.diary-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    overflow-y: auto;
    padding-right: 0.25rem;
}

.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--text-muted);
}

.empty-icon {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    display: block;
}

.empty-state p {
    font-size: 0.85rem;
}

/* Diary Card Item */
.diary-item {
    background: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--card-border);
    border-radius: 12px;
    padding: 1rem;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    position: relative;
    transition: all var(--transition-fast);
}

.diary-item:hover {
    background: rgba(255, 255, 255, 0.04);
    border-color: var(--text-muted);
}

.diary-item-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.item-date {
    font-family: var(--font-display);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.item-mood-badge {
    background: rgba(255, 255, 255, 0.05);
    padding: 0.2rem 0.5rem;
    border-radius: 20px;
    font-size: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.25rem;
    font-weight: 600;
}

.diary-item-body {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}

.sentence-line {
    font-size: 0.9rem;
    line-height: 1.45;
    padding-left: 0.75rem;
    border-left: 2px solid var(--primary);
}

.sentence-line:nth-child(2) {
    border-left-color: var(--accent);
}

.sentence-line:nth-child(3) {
    border-left-color: var(--success);
}

.diary-item-actions {
    display: flex;
    justify-content: flex-end;
    gap: 0.5rem;
    margin-top: 0.25rem;
}

.btn-text {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 0.75rem;
    cursor: pointer;
    font-weight: 600;
    transition: color var(--transition-fast);
}

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

.btn-text.delete:hover {
    color: var(--accent);
}

/* Settings and Backup */
.settings-card h4 {
    font-family: var(--font-display);
    font-size: 0.95rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
}

.settings-buttons {
    display: flex;
    gap: 0.5rem;
}

.btn-secondary {
    flex: 1;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--card-border);
    color: var(--text-secondary);
    padding: 0.6rem;
    border-radius: 8px;
    font-size: 0.8rem;
    font-family: var(--font-display);
    font-weight: 600;
    cursor: pointer;
    text-align: center;
    transition: all var(--transition-fast);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-primary);
    border-color: var(--text-muted);
}

.file-label {
    display: flex;
    justify-content: center;
    align-items: center;
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(4px);
    z-index: 1000;
    justify-content: center;
    align-items: center;
}

.modal-content {
    width: 90%;
    max-width: 500px;
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-header h3 {
    font-family: var(--font-display);
    font-size: 1.2rem;
    font-weight: 700;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-muted);
    cursor: pointer;
}

.close-btn:hover {
    color: var(--text-primary);
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 0.5rem;
    margin-top: 1rem;
}