/* CSS Variables - Light Theme (Default) */
:root {
    --primary: #6b8a9b;
    --primary-hover: #5a7884;
    --primary-light: #8ba5b3;
    --success: #7aa592;
    --warning: #c8a882;
    --danger: #b8847a;
    --text: #2c2c2c;
    --text-light: #5c5c5c;
    --text-muted: #8a8a8a;
    --bg: #f7f6f4;
    --bg-gray: #f2f1ee;
    --bg-light: #e8e6e1;
    --bg-card: #fdfcfa;
    --border: #d4d2cd;
    --border-light: #e2e0db;
    --shadow: 0 2px 8px rgba(60, 60, 60, 0.08);
    --shadow-lg: 0 8px 32px rgba(60, 60, 60, 0.12);
    --shadow-subtle: 0 1px 4px rgba(60, 60, 60, 0.05);
    --radius: 0.625rem;
    --accent: #9bb3c1;
    --accent-hover: #8ba5b3;
    /* Campaign Colors */
    --campaign-free-bg: #b8717a;
    --campaign-free-bg-light: #9e6068;
    --campaign-free-text: #b8717a;
    --campaign-free-text-light: #9e6068;
    --campaign-discount-bg: #b89965;
    --campaign-discount-bg-light: #a0834e;
    --campaign-discount-text: #b89965;
    --campaign-discount-text-light: #a0834e;
}

/* Dark Theme */
[data-theme="dark"] {
    --primary: #8ba5b3;
    --primary-hover: #9bb3c1;
    --primary-light: #a3bcc7;
    --success: #82a394;
    --warning: #c2a688;
    --danger: #b8958a;
    --text: #e8e6e1;
    --text-light: #c4c2bd;
    --text-muted: #9a9893;
    --bg: #333333;
    --bg-gray: #2b2b2b;
    --bg-light: #424242;
    --bg-card: #3a3a3a;
    --border: #4e4e49;
    --border-light: #5a5a55;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
    --shadow-subtle: 0 1px 4px rgba(0, 0, 0, 0.15);
    --accent: #6b8a9b;
    --accent-hover: #5a7884;
    /* Campaign Colors */
    --campaign-free-bg: #d4a5a5;
    --campaign-free-bg-light: #c19090;
    --campaign-free-text: #d4a5a5;
    --campaign-free-text-light: #c19090;
    --campaign-discount-bg: #e6c785;
    --campaign-discount-bg-light: #d9b96f;
    --campaign-discount-text: #e6c785;
    --campaign-discount-text-light: #d9b96f;
}

/* System preference fallback (if no manual selection) */
@media (prefers-color-scheme: dark) {
    :root:not([data-theme]) {
        --primary: #8ba5b3;
        --primary-hover: #9bb3c1;
        --primary-light: #a3bcc7;
        --success: #82a394;
        --warning: #c2a688;
        --danger: #b8958a;
        --text: #e8e6e1;
        --text-light: #c4c2bd;
        --text-muted: #9a9893;
        --bg: #333333;
        --bg-gray: #2b2b2b;
        --bg-light: #424242;
        --bg-card: #3a3a3a;
        --border: #4e4e49;
        --border-light: #5a5a55;
        --shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
        --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
        --shadow-subtle: 0 1px 4px rgba(0, 0, 0, 0.15);
        --accent: #6b8a9b;
        --accent-hover: #5a7884;
        /* Campaign Colors */
        --campaign-free-bg: #d4a5a5;
        --campaign-free-bg-light: #c19090;
        --campaign-free-text: #d4a5a5;
        --campaign-free-text-light: #c19090;
        --campaign-discount-bg: #e6c785;
        --campaign-discount-bg-light: #d9b96f;
        --campaign-discount-text: #e6c785;
        --campaign-discount-text-light: #d9b96f;
    }
}

/* Reset */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    transition: background-color 0.3s ease;
}

body {
    font-family: 'Noto Sans JP', system-ui, sans-serif;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg-gray);
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Skip link for screen readers */
.skip-link {
    position: absolute;
    top: -100px;
    left: 6px;
    background: var(--primary);
    color: white;
    padding: 8px;
    text-decoration: none;
    border-radius: 0 0 4px 4px;
    z-index: 1000;
    opacity: 0;
    transform: translateY(-10px);
    transition: all 0.3s ease;
}

.skip-link:focus {
    top: 0;
    opacity: 1;
    transform: translateY(0);
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
.header {
    background: var(--bg);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
    transition: background-color 0.3s ease;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1rem 0;
    min-height: 64px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    transition: color 0.3s ease;
}

.logo:hover {
    color: var(--primary-hover);
}

.logo-text {
    font-weight: 700;
    font-size: 1.5rem;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Navigation */
.nav {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.nav-link {
    color: var(--text-light);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: var(--radius);
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: var(--primary);
    background: var(--bg-light);
}

.nav-link[aria-current="page"] {
    color: var(--primary);
    background: var(--bg-light);
}

.nav-link[aria-current="page"]::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 2px;
    background: var(--primary);
    border-radius: 2px;
}

/* Theme Toggle Button */
.theme-toggle {
    background: var(--bg-light);
    border: 2px solid var(--border);
    border-radius: 36px;
    padding: 3px;
    cursor: pointer;
    display: flex;
    align-items: center;
    width: 76px;
    height: 40px;
    transition: all 0.3s ease;
    margin-left: 0.5rem;
    position: relative;
    overflow: hidden;
}

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

.theme-toggle:focus {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

.theme-slider {
    width: 30px;
    height: 30px;
    background: var(--bg);
    border-radius: 50%;
    position: absolute;
    left: 4px;
    top: 4px;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
    border: 1px solid var(--border);
}

[data-theme="dark"] .theme-slider {
    left: 41px;
    background: var(--bg);
}

.theme-icons {
    position: absolute;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 12px;
    pointer-events: none;
}

.theme-icon {
    width: 20px;
    height: 20px;
    transition: all 0.3s ease;
    color: var(--text-muted);
}

.sun-icon {
    opacity: 1;
}

.moon-icon {
    opacity: 1;
}

[data-theme="dark"] .sun-icon {
    opacity: 0.3;
}

[data-theme="dark"] .moon-icon {
    opacity: 1;
    color: var(--text-light);
}

[data-theme="light"] .sun-icon {
    opacity: 1;
    color: var(--warning);
}

[data-theme="light"] .moon-icon {
    opacity: 0.3;
}

.theme-toggle:hover .theme-icon {
    opacity: 1;
}

/* Main */
.main {
    min-height: calc(100vh - 128px);
    padding: 2rem 0;
}

/* Card */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-light);
    border-radius: var(--radius);
    box-shadow: var(--shadow-subtle);
    padding: 2rem;
    margin-bottom: 2rem;
    transition: all 0.3s ease;
}

.card:hover {
    box-shadow: var(--shadow);
    transform: translateY(-1px);
}

/* Form Elements */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: var(--text);
    transition: color 0.3s ease;
}

.form-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-size: 1rem;
    background: var(--bg);
    color: var(--text);
    transition: all 0.3s ease;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary);
}

.form-input::placeholder {
    color: var(--text-muted);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    min-height: 44px;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
}

.btn-secondary {
    background: var(--bg-light);
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: var(--border);
}

/* Utilities */
.text-center {
    text-align: center;
}

.text-muted {
    color: var(--text-muted);
}

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

/* Footer */
.footer {
    background: var(--bg-card);
    border-top: 1px solid var(--border-light);
    margin-top: 4rem;
    padding: 3rem 0 1rem;
    transition: background-color 0.3s ease;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section {
    display: flex;
    flex-direction: column;
}

.footer-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 1rem;
}

.footer-description {
    color: var(--text-light);
    line-height: 1.6;
    font-size: 0.875rem;
}

.footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-link {
    color: var(--text-light);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color 0.3s ease;
}

.footer-link:hover {
    color: var(--primary);
}

.footer-bottom {
    border-top: 1px solid var(--border-light);
    padding-top: 2rem;
    text-align: center;
    color: var(--text-muted);
    font-size: 0.875rem;
}

.footer-bottom p {
    margin: 0 0 0.5rem 0;
}

.footer-note {
    font-size: 0.75rem;
    color: var(--text-muted);
    line-height: 1.4;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 0 0.75rem;
    }
    
    .header-content {
        min-height: 56px;
    }
    
    .logo {
        font-size: 1.25rem;
    }
    
    .nav {
        gap: 0.5rem;
    }
    
    .nav-link {
        padding: 0.375rem 0.75rem;
        font-size: 0.875rem;
    }
    
    .theme-toggle {
        width: 70px;
        height: 38px;
    }
    
    .theme-slider {
        width: 28px;
        height: 28px;
        left: 5px;
        top: 5px;
    }
    
    [data-theme="dark"] .theme-slider {
        left: 37px;
    }
    
    .theme-icons {
        padding: 0 11px;
    }
    
    .theme-icon {
        width: 18px;
        height: 18px;
    }
    
    .card {
        padding: 1.5rem;
    }
    
    .main {
        padding: 1.5rem 0;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .footer {
        padding: 2rem 0 1rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 0.5rem;
    }
    
    .card {
        padding: 1rem;
    }
    
    .main {
        padding: 1rem 0;
    }
    
    .theme-toggle {
        width: 66px;
        height: 36px;
    }
    
    .theme-slider {
        width: 28px;
        height: 28px;
        left: 5px;
        top: 5px;
    }
    
    [data-theme="dark"] .theme-slider {
        left: 35px;
    }
    
    .theme-icons {
        padding: 0 10px;
    }
    
    .theme-icon {
        width: 16px;
        height: 16px;
    }

    .footer-content {
        text-align: center;
    }

    .footer-bottom {
        padding-top: 1rem;
    }
}