/* Base styles */
:root {
    --primary-color: #4A90E2;
    --secondary-color: #7FBA00;
    --danger-color: #E74C3C;
    --warning-color: #F39C12;
    --text-dark: #2C3E50;
    --text-light: #7F8C8D;
    --bg-light: #F8F9FA;
    --border-color: #DEE2E6;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", 
                 "Noto Sans CJK JP", sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-light);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navbar */
.navbar {
    background: white;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    padding: 1rem 0;
}

.navbar-brand a {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

.navbar-menu {
    list-style: none;
    display: flex;
    gap: 1rem;
    align-items: center;
    margin: 0;
    padding: 0;
}

.navbar-menu a {
    color: var(--text-dark);
    text-decoration: none;
}

/* Hero section */
.hero {
    text-align: center;
    padding: 4rem 0;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.hero h2 {
    font-size: 2rem;
    color: var(--text-light);
    margin-bottom: 1rem;
}

.lead {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
}

/* Features */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    padding: 3rem 0;
}

.feature {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    text-align: center;
}

.feature h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

/* Alert messages */
.alert {
    padding: 1rem;
    margin: 1rem 0;
    border-radius: 4px;
}

.alert-success {
    background-color: #D4EDDA;
    border-color: #C3E6CB;
    color: #155724;
}

.alert-warning {
    background-color: #FFF3CD;
    border-color: #FFEEBA;
    color: #856404;
}

.alert-danger {
    background-color: #F8D7DA;
    border-color: #F5C6CB;
    color: #721C24;
}

.alert-info {
    background-color: #D1ECF1;
    border-color: #BEE5EB;
    color: #0C5460;
}

.alert-error {
    background-color: #F8D7DA;
    border-color: #F5C6CB;
    color: #721C24;
}

/* Footer */
.footer {
    background: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
    border-top: 1px solid var(--border-color);
}

/* Error pages */
.error-page {
    text-align: center;
    padding: 4rem 0;
}

.error-page h1 {
    font-size: 6rem;
    color: var(--primary-color);
}

.error-page h2 {
    font-size: 2rem;
    margin: 1rem 0;
}

.error-page a {
    display: inline-block;
    margin-top: 2rem;
    padding: 0.75rem 2rem;
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 4px;
}

.error-page a:hover {
    background: #3A7BC8;
}

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero h2 {
        font-size: 1.5rem;
    }
}