:root {
    --primary-color: #6c5ce7;
    --primary-light: #a29bfe;
    --secondary-color: #fd79a8;
    --success-color: #00b894;
    --warning-color: #fdcb6e;
    --danger-color: #e17055;
    --bg-color: #fafafa;
    --card-bg: #ffffff;
    --text-color: #2d3436;
    --text-secondary: #636e72;
    --border-color: #dfe6e9;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --gradient: linear-gradient(135deg, #6c5ce7 0%, #a29bfe 100%);
}

.dark {
    --bg-color: #1a1a2e;
    --card-bg: #16213e;
    --text-color: #e8e8e8;
    --text-secondary: #b2bec3;
    --border-color: #2d3436;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    margin-bottom: 30px;
}

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

.logo {
    font-size: 1.8rem;
    font-weight: 700;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.theme-toggle {
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 44px;
    height: 44px;
    font-size: 1.5rem;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow);
}

.main-nav {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 30px;
    background: var(--card-bg);
    padding: 10px;
    border-radius: 16px;
    box-shadow: var(--shadow);
}

.nav-item {
    padding: 10px 20px;
    border-radius: 10px;
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: all 0.3s;
}

.nav-item:hover, .nav-item.active {
    background: var(--gradient);
    color: white;
}

.hero {
    text-align: center;
    padding: 40px 20px;
    background: var(--gradient);
    border-radius: 20px;
    color: white;
    margin-bottom: 40px;
}

.hero h2 {
    font-size: 2rem;
    margin-bottom: 10px;
}

.hero p {
    font-size: 1.1rem;
    opacity: 0.9;
}

section {
    margin-bottom: 40px;
}

section h3 {
    font-size: 1.5rem;
    margin-bottom: 20px;
    color: var(--text-color);
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 25px;
    text-decoration: none;
    color: var(--text-color);
    box-shadow: var(--shadow);
    transition: all 0.3s;
    display: block;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.card-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.card h4 {
    font-size: 1.2rem;
    margin-bottom: 8px;
}

.card p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.holiday-list, .memorial-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.holiday-item, .memorial-item {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow);
    transition: all 0.3s;
}

.holiday-item:hover, .memorial-item:hover {
    transform: translateX(5px);
}

.holiday-info, .memorial-info {
    flex: 1;
}

.holiday-name, .memorial-name {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 5px;
}

.holiday-date, .memorial-date {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.holiday-countdown, .memorial-countdown {
    text-align: right;
}

.countdown-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
}

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

.form-section {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 16px;
    box-shadow: var(--shadow);
    margin-bottom: 30px;
}

.form-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-color);
}

input[type="text"],
input[type="date"],
select {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    font-size: 1rem;
    background: var(--bg-color);
    color: var(--text-color);
    transition: border-color 0.3s;
}

input:focus, select:focus {
    outline: none;
    border-color: var(--primary-color);
}

.btn {
    padding: 14px 28px;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
}

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

.btn-primary:hover {
    transform: scale(1.02);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background: var(--card-bg);
    color: var(--text-color);
    border: 2px solid var(--border-color);
}

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

.btn-group {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.result-section {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 16px;
    box-shadow: var(--shadow);
    text-align: center;
}

.result-value {
    font-size: 3.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 20px 0;
}

.result-label {
    font-size: 1.2rem;
    color: var(--text-secondary);
}

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

.delete-btn {
    background: transparent;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 5px 10px;
    opacity: 0.6;
    transition: opacity 0.3s;
}

.delete-btn:hover {
    opacity: 1;
}

footer {
    margin-top: auto;
    text-align: center;
    padding: 30px 0;
    color: var(--text-secondary);
}

@media (max-width: 768px) {
    .logo {
        font-size: 1.4rem;
    }

    .hero h2 {
        font-size: 1.5rem;
    }

    .nav-item {
        padding: 8px 14px;
        font-size: 0.9rem;
    }

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

    .result-value {
        font-size: 2.5rem;
    }

    .holiday-item, .memorial-item {
        flex-direction: column;
        gap: 15px;
    }

    .holiday-countdown, .memorial-countdown {
        text-align: center;
    }
}