:root {
    --aka-red: #1565c0;
    --kobicha: #6B4226;
    --byakuroku: #A8D8B9;
    --sakura: #F9E3E6;
    --kumo-iro: #D4D8DD;
    --sumi: #1C1C1C;
    --usu-cha: #A89F91;
    
    --primary-color: var(--aka-red);
    --primary-light: #42a5f5;
    --primary-dark: #003c8f;
    --secondary-color: var(--kobicha);
    --accent-color: var(--byakuroku);
    --background-color: #FAFAFA;
    --surface-color: #FFFFFF;
    --card-background: #e3f2fd;
    --content-background: var(--kumo-iro);
    --text-primary: var(--sumi);
    --text-secondary: var(--kobicha);
    --text-muted: var(--usu-cha);
    --border-color: var(--usu-cha);
    --border-light: rgba(169, 159, 145, 0.3);
    
    --shadow-sm: 0 1px 3px rgba(28, 28, 28, 0.08);
    --shadow-md: 0 4px 12px rgba(28, 28, 28, 0.12);
    --shadow-lg: 0 8px 24px rgba(28, 28, 28, 0.15);
    --shadow-xl: 0 16px 32px rgba(28, 28, 28, 0.18);
    --shadow-2xl: 0 25px 50px rgba(28, 28, 28, 0.25);
    
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-2xl: 32px;
    --radius-full: 50px;
    
    --space-1: 0.5rem;
    --space-2: 1rem;
    --space-3: 1.5rem;
    --space-4: 2rem;
    --space-5: 2.5rem;
    --space-6: 3rem;
    --space-8: 4rem;
    --space-12: 6rem;
    --space-16: 8rem;

    --ease-out-cubic: cubic-bezier(0.215, 0.610, 0.355, 1);
    --ease-in-out-cubic: cubic-bezier(0.645, 0.045, 0.355, 1);

    /* Advanced Responsive Variables */
    --container-padding: clamp(1rem, 4vw, 2rem);
    --section-spacing: clamp(3rem, 8vw, 6rem);
    --element-gap: clamp(1rem, 3vw, 2rem);
    --header-height: clamp(4rem, 6vw, 5rem);
    --safe-area-top: env(safe-area-inset-top, 0px);
    --safe-area-bottom: env(safe-area-inset-bottom, 0px);
    --safe-area-left: env(safe-area-inset-left, 0px);
    --safe-area-right: env(safe-area-inset-right, 0px);
}

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

html {
    scroll-behavior: smooth;
    font-size: clamp(14px, 1.5vw, 16px);
    line-height: 1.5;
    -webkit-text-size-adjust: 100%;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--background-color);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
    width: 100%;
    min-height: 100vh;
    position: relative;
}

/* Advanced Container System */
.container {
    width: 100%;
    max-width: min(1400px, calc(100vw - var(--container-padding) * 2));
    margin-inline: auto;
    padding-inline: var(--container-padding);
    position: relative;
}

.container-fluid {
    width: 100%;
    padding-inline: var(--container-padding);
    position: relative;
}

/* Advanced Grid System */
.grid {
    display: grid;
    gap: var(--element-gap);
}

.grid-auto-fit {
    grid-template-columns: repeat(auto-fit, minmax(min(280px, 100%), 1fr));
}

.grid-auto-fill {
    grid-template-columns: repeat(auto-fill, minmax(min(280px, 100%), 1fr));
}

/* Flexible Layout System */
.flex {
    display: flex;
    gap: var(--element-gap);
}

.flex-col {
    flex-direction: column;
}

.flex-wrap {
    flex-wrap: wrap;
}

.items-center {
    align-items: center;
}

.justify-center {
    justify-content: center;
}

.justify-between {
    justify-content: space-between;
}

/* Advanced Header with No Overlap */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    padding: 0.5rem 1rem;
}

.header-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
}

.header-brand {
    display: flex;
    align-items: center;
    gap: 1rem;
    text-decoration: none;
}

.brand-logo {
    width: 40px;
    height: 40px;
    object-fit: contain;
    border-radius: 8px;
    margin-right: 0.75rem;
}

.brand-info {
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.brand-text {
    color: var(--text-primary);
    font-size: 1.2rem;
    font-weight: 600;
}

.brand-subtitle {
    color: var(--text-muted);
    font-size: 0.8rem;
    display: block;
}

.header-nav {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.nav-link {
    color: var(--text-primary);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 500;
}

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

.login-btn {
    background: var(--primary-color);
    color: white;
    padding: 0.5rem 1.5rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.login-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    padding: 0.5rem;
    cursor: pointer;
    color: var(--text-primary);
}

@media (max-width: 992px) {
    .header-nav {
        display: none;
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        background: white;
        padding: 1rem;
        flex-direction: column;
        align-items: stretch;
        gap: 0.5rem;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    }
    .header-nav.active {
        display: flex;
    }
    .nav-link {
        padding: 0.75rem 1rem;
        display: block;
    }
    .mobile-menu-btn {
        display: block;
    }
    .login-btn {
        margin-top: 0.5rem;
        text-align: center;
        display: block;
    }
}

@media (max-width: 768px) {
    .header {
        padding: 0.5rem;
    }
    .brand-text {
        font-size: 1rem;
    }
    .brand-subtitle {
        font-size: 0.7rem;
    }
    .brand-logo {
        width: 32px;
        height: 32px;
    }
}