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

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --secondary-color: #ec4899;
    --background: #0f172a;
    --surface: #1e293b;
    --surface-light: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border-radius: 16px;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -4px rgba(0, 0, 0, 0.2);
}

body {
    font-family: 'Segoe UI', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--background);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header Styles */
header {
    text-align: center;
    padding: 40px 20px;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

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

/* Main Content */
main {
    flex: 1;
}

/* Input Section */
.input-section {
    background: var(--surface);
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    text-align: center;
    margin-bottom: 30px;
}

.input-section label {
    display: block;
    font-size: 1.1rem;
    margin-bottom: 15px;
    color: var(--text-secondary);
}

.input-section input[type="date"] {
    width: 100%;
    max-width: 300px;
    padding: 15px 20px;
    font-size: 1.1rem;
    border: 2px solid var(--surface-light);
    border-radius: 12px;
    background: var(--background);
    color: var(--text-primary);
    cursor: pointer;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.input-section input[type="date"]:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.input-section input[type="date"]::-webkit-calendar-picker-indicator {
    filter: invert(1);
    cursor: pointer;
}

#calculate-btn {
    display: block;
    width: 100%;
    max-width: 300px;
    margin: 20px auto 0;
    padding: 15px 30px;
    font-size: 1.1rem;
    font-weight: 600;
    color: white;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border: none;
    border-radius: 12px;
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

#calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

#calculate-btn:active {
    transform: translateY(0);
}

/* Results Section */
.results-section {
    display: grid;
    gap: 20px;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Result Cards */
.result-card {
    background: var(--surface);
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.result-card h2 {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 20px;
    text-align: center;
}

/* Age Display */
.age-display {
    display: flex;
    justify-content: center;
    gap: 30px;
    flex-wrap: wrap;
}

.age-unit {
    text-align: center;
}

.age-number {
    display: block;
    font-size: 3rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.age-label {
    display: block;
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-top: 5px;
}

/* Birthday Card */
.birthday-info {
    text-align: center;
}

#days-until {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--secondary-color);
    margin-bottom: 10px;
}

#next-birthday-date {
    color: var(--text-secondary);
}

/* Zodiac Cards */
.zodiac-info,
.chinese-zodiac-info {
    text-align: center;
}

.zodiac-symbol,
.chinese-zodiac-symbol {
    display: block;
    font-size: 4rem;
    margin-bottom: 10px;
}

.zodiac-name,
.chinese-zodiac-name {
    display: block;
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.zodiac-dates,
.chinese-zodiac-element {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

/* Stats Grid */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}

.stat-item {
    text-align: center;
    padding: 15px;
    background: var(--background);
    border-radius: 12px;
}

.stat-number {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 5px;
}

.stat-label {
    display: block;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

/* Footer */
footer {
    text-align: center;
    padding: 30px 20px;
    margin-top: 40px;
    border-top: 1px solid var(--surface-light);
}

footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

footer a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s ease;
}

footer a:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

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

    .subtitle {
        font-size: 1rem;
    }

    .input-section {
        padding: 20px;
    }

    .age-number {
        font-size: 2.5rem;
    }

    .age-display {
        gap: 20px;
    }

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

    .result-card {
        padding: 20px;
    }

    .zodiac-symbol,
    .chinese-zodiac-symbol {
        font-size: 3rem;
    }
}

@media (max-width: 400px) {
    .container {
        padding: 15px;
    }

    header {
        padding: 30px 15px;
    }

    header h1 {
        font-size: 1.75rem;
    }

    .age-number {
        font-size: 2rem;
    }

    .age-display {
        gap: 15px;
    }
}

/* Dark Mode Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--background);
}

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

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-color);
}