:root {
    /* Dark Theme (Default) */
    --bg-color: #191919;
    --card-bg: #191919;
    --card-hover: #2F2F2F;
    --text-primary: rgba(255, 255, 255, 0.9);
    --text-secondary: rgba(255, 255, 255, 0.445);
    --accent: #ffffff;
    /* Neutral White Accent */
    --accent-glow: rgba(255, 255, 255, 0.1);
    --border: rgba(255, 255, 255, 0.09);
    --font-main: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, "Apple Color Emoji", Arial, sans-serif, "Segoe UI Emoji", "Segoe UI Symbol";
    --font-mono: 'JetBrains Mono', monospace;
    --transition: all 0.2s ease-in-out;
}

[data-theme="light"] {
    --bg-color: #ffffff;
    --card-bg: #ffffff;
    --card-hover: #F7F7F5;
    --text-primary: #37352F;
    --text-secondary: rgba(55, 53, 47, 0.65);
    --accent: #37352F;
    /* Neutral Dark Accent */
    --accent-glow: rgba(55, 53, 47, 0.09);
    --border: rgba(55, 53, 47, 0.09);
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-main);
    min-height: 100vh;
    overflow-x: hidden;
    display: flex;
    flex-direction: column;
}

.background-glow {
    position: fixed;
    top: -20%;
    left: -20%;
    width: 140%;
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem 4rem;
}

/* Header */
header {
    padding: 2rem 1.5rem 0;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

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

.logo .icon {
    background: var(--text-primary);
    color: var(--bg-color);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    /* More boxy like Notion */
    font-weight: 700;
    font-size: 1.2rem;
    box-shadow: none;
    /* Remove glow */
}

h1 {
    font-size: 1.8rem;
    font-weight: 600;
    letter-spacing: -0.5px;
}

.theme-toggle {
    background: transparent;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 4px;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background: var(--card-hover);
    color: var(--text-primary);
}

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

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

[data-theme="light"] .sun-icon {
    display: none;
}

[data-theme="light"] .moon-icon {
    display: block;
}

.subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    font-size: 1.1rem;
}

/* Controls */
.controls {
    margin-bottom: 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    align-items: center;
}

.search-container {
    position: relative;
    width: 100%;
    max-width: 600px;
}

.search-icon {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    pointer-events: none;
}

#searchInput {
    width: 100%;
    padding: 1rem 1rem 1rem 3rem;
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 4px;
    /* More boxy */
    color: var(--text-primary);
    font-family: var(--font-main);
    font-size: 1.1rem;
    transition: var(--transition);
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

#searchInput:focus {
    outline: none;
    border-color: var(--text-secondary);
    box-shadow: 0 0 0 2px var(--accent-glow);
}

.filter-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
}

.filter-btn {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    padding: 0.5rem 1rem;
    border-radius: 4px;
    /* More boxy */
    cursor: pointer;
    font-family: var(--font-main);
    font-size: 0.95rem;
    transition: var(--transition);
}

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

.filter-btn.active {
    background: var(--text-primary);
    border-color: var(--text-primary);
    color: var(--bg-color);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

/* Grid */
.unicode-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
    gap: 1rem;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.char-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    border-radius: 4px;
    /* More boxy */
    padding: 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    aspect-ratio: 1;
    position: relative;
    overflow: hidden;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.02);
}

.char-card:hover {
    transform: translateY(-2px);
    background: var(--card-hover);
    border-color: var(--text-secondary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
}

.char-card:active {
    transform: scale(0.98);
}

.char-display {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    line-height: 1;
}

.char-info {
    text-align: center;
    opacity: 0.7;
}

.char-code {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-secondary);
    display: block;
}

.char-name {
    font-size: 0.7rem;
    display: block;
    margin-top: 0.25rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 100%;
}

/* Loading & No Results */
.hidden {
    display: none !important;
}

.loading {
    display: flex;
    justify-content: center;
    padding: 4rem;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--card-bg);
    border-top-color: var(--text-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.no-results {
    text-align: center;
    padding: 4rem;
    color: var(--text-secondary);
    font-size: 1.2rem;
}

/* Toast */
.toast {
    position: fixed;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--text-primary);
    color: var(--bg-color);
    padding: 0.75rem 1.5rem;
    border-radius: 4px;
    font-weight: 600;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    opacity: 0;
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275), opacity 0.3s;
    z-index: 100;
}

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

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
    border-top: 1px solid var(--border);
    margin-top: auto;
}

/* Responsive */
@media (max-width: 600px) {
    h1 {
        font-size: 2rem;
    }

    .unicode-grid {
        grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
    }

    .char-display {
        font-size: 2rem;
    }
}