:root {
    --bg-color: #0f172a;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #38bdf8;
    --accent-glow: rgba(56, 189, 248, 0.3);
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.1);
    --input-bg: rgba(15, 23, 42, 0.6);
    --highlight-match: rgba(56, 189, 248, 0.25);
    --highlight-border: #38bdf8;
    --error-color: #ef4444;
    --success-color: #22c55e;
    --font-family: 'Outfit', sans-serif;
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 2rem;
    overflow-x: hidden;
    position: relative;
}

.background-glow {
    position: fixed;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at center, rgba(56, 189, 248, 0.1) 0%, transparent 50%);
    z-index: -1;
    pointer-events: none;
}

.container {
    width: 100%;
    max-width: 1400px;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.app-header {
    text-align: center;
    margin-bottom: 1rem;
}

.app-header h1 {
    font-size: 3rem;
    font-weight: 700;
    background: linear-gradient(135deg, #fff 0%, #38bdf8 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
}

.app-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.glass-panel {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.glass-panel:hover {
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.3);
    border-color: rgba(255, 255, 255, 0.15);
}

.input-group {
    margin-bottom: 1.5rem;
}

.input-group:last-child {
    margin-bottom: 0;
}

label {
    display: block;
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.regex-input-wrapper {
    display: flex;
    align-items: center;
    background: var(--input-bg);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    padding: 0.5rem 1rem;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 1.1rem;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.regex-input-wrapper:focus-within {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.slash {
    color: var(--text-secondary);
    font-weight: bold;
    user-select: none;
}

#regex-input {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-family: inherit;
    font-size: inherit;
    padding: 0 0.5rem;
    outline: none;
}

#flags-input {
    width: 60px;
    background: transparent;
    border: none;
    color: var(--success-color);
    font-family: inherit;
    font-size: inherit;
    padding: 0 0.5rem;
    outline: none;
    font-style: italic;
}

#test-string {
    width: 100%;
    height: 150px;
    background: var(--input-bg);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    padding: 1rem;
    color: var(--text-primary);
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 1rem;
    line-height: 1.5;
    resize: vertical;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

#test-string:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.error-message {
    color: var(--error-color);
    font-size: 0.85rem;
    margin-top: 0.5rem;
    min-height: 1.2em;
    font-weight: 500;
}

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

.panel-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
}

.badge {
    background: var(--accent-color);
    color: #000;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 700;
    box-shadow: 0 2px 10px var(--accent-glow);
}

.results-content {
    background: var(--input-bg);
    border: 1px solid var(--glass-border);
    border-radius: 8px;
    padding: 1rem;
    min-height: 150px;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 1rem;
    line-height: 1.5;
    white-space: pre-wrap;
    word-break: break-all;
    color: var(--text-secondary);
}

.match {
    background-color: var(--highlight-match);
    border-bottom: 2px solid var(--highlight-border);
    color: var(--text-primary);
    border-radius: 2px;
}

/* Scrollbar styling */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--glass-border);
    border-radius: 4px;
}

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

/* Samples Panel */
.samples-grid {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.sample-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid var(--glass-border);
    border-radius: 12px;
    padding: 1rem;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: center;
}

.sample-card:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--accent-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.sample-card h3 {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
    color: var(--text-primary);
}

.sample-card span {
    font-size: 0.75rem;
    color: var(--text-secondary);
}

/* Layout Refactoring */
.content-wrapper {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
    align-items: start;
}

.main-content {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.sidebar {
    position: sticky;
    top: 2rem;
}

@media (max-width: 1024px) {
    .content-wrapper {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
    }

    .samples-grid {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    }
}