:root {
    --primary-color: #2563eb;
    --secondary-color: #0d47a1;
    --accent-color: #10b981;
    --accent-secondary: #7c3aed;
    --text-color: #1e293b;
    --light-bg: #f8fafc;
    --dark-bg: #0f172a;
    --white: #ffffff;
    --gray: #e2e8f0;
    --gray-light: #f1f5f9;
    --border-color: #cbd5e1;
    --success-color: #10b981;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    -webkit-tap-highlight-color: transparent;
}

body {
    background-color: var(--light-bg);
    color: var(--text-color);
    font-size: 16px;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    text-decoration: none;
    color: var(--primary-color);
}

.app-container {
    max-width: 100%;
    margin: 0 auto;
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* App Header */
.app-header {
    background-color: var(--white);
    padding: 15px 20px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.app-logo {
    font-size: 20px;
    font-weight: 700;
    color: var(--primary-color);
    display: flex;
    align-items: center;
}

.app-logo span {
    color: var(--accent-color);
}

.app-logo-icon {
    margin-right: 8px;
    font-size: 24px;
}

.menu-button {
    background: none;
    border: none;
    font-size: 24px;
    color: var(--text-color);
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
}

.menu-button:active {
    background-color: var(--gray-light);
}

/* App Content */
.app-content {
    flex: 1;
    padding-bottom: 60px; /* Space for bottom nav */
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px 15px 40px;
}

.title {
    font-size: 24px;
    font-weight: 800;
    margin-bottom: 20px;
    text-align: center;
}

/* カテゴリフィルター */
.category-filter {
    display: flex;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    -ms-overflow-style: none;
    margin-bottom: 20px;
    padding-bottom: 10px;
    white-space: nowrap;
    gap: 10px;
}

.category-filter::-webkit-scrollbar {
    display: none;
}

.category-button {
    padding: 8px 15px;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    background-color: var(--white);
    font-size: 14px;
    color: var(--text-color);
    font-weight: 500;
    white-space: nowrap;
}

.category-button.active {
    background-color: var(--primary-color);
    color: var(--white);
    border-color: var(--primary-color);
}

/* コラムリスト */
.column-list {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.column-card {
    background-color: var(--white);
    border-radius: 12px;
    box-shadow: var(--card-shadow);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    color: var(--text-color);
    transition: transform 0.2s ease;
}

.column-card:active {
    transform: translateY(-2px);
}

.column-image {
    width: 100%;
    height: 120px;
    background-color: var(--gray-light);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 40px;
}

.column-meta {
    display: flex;
    justify-content: space-between;
    padding: 10px 15px 0;
    font-size: 12px;
    color: #64748b;
}

.column-content {
    flex: 1;
    padding: 10px 15px 15px;
}

.column-title {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 8px;
    line-height: 1.3;
}

.column-excerpt {
    font-size: 14px;
    color: #64748b;
    margin-bottom: 0;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    line-height: 1.4;
}

.column-date {
    color: #94a3b8;
}

.column-category {
    background-color: var(--gray-light);
    padding: 2px 8px;
    border-radius: 10px;
    font-weight: 500;
}

/* Bottom Navigation */
.bottom-nav {
    background-color: var(--white);
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    box-shadow: 0 -1px 3px rgba(0, 0, 0, 0.1);
    z-index: 100;
}

.nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 10px 0;
    color: #64748b;
}

.nav-item.active {
    color: var(--primary-color);
}

.nav-icon {
    font-size: 20px;
    margin-bottom: 4px;
}

.nav-label {
    font-size: 12px;
    font-weight: 500;
}

/* Mobile Menu */
.mobile-menu {
    position: fixed;
    top: 0;
    right: 0;
    bottom: 0;
    background-color: var(--white);
    width: 80%;
    max-width: 300px;
    z-index: 200;
    transform: translateX(100%);
    transition: transform 0.3s ease;
    box-shadow: -2px 0 10px rgba(0, 0, 0, 0.1);
    display: flex;
    flex-direction: column;
}

.mobile-menu.open {
    transform: translateX(0);
}

.menu-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 199;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.menu-overlay.open {
    opacity: 1;
    visibility: visible;
}

.menu-header {
    padding: 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--gray);
}

.menu-close {
    background: none;
    border: none;
    font-size: 24px;
    color: var(--text-color);
    cursor: pointer;
}

.menu-user {
    display: flex;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid var(--gray);
}

.user-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background-color: var(--gray);
    margin-right: 15px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    color: var(--white);
    background-color: var(--primary-color);
}

.user-name {
    font-weight: 600;
    margin-bottom: 5px;
}

.user-email {
    font-size: 14px;
    color: #64748b;
}

.menu-items {
    flex: 1;
    overflow-y: auto;
    padding: 10px 0;
}

.menu-item {
    display: flex;
    align-items: center;
    padding: 15px 20px;
    color: var(--text-color);
}

.menu-item:active {
    background-color: var(--gray-light);
}

.menu-item-icon {
    margin-right: 15px;
    font-size: 20px;
    width: 24px;
    text-align: center;
}

.menu-footer {
    padding: 20px;
    border-top: 1px solid var(--gray);
}

.logout-button {
    display: flex;
    align-items: center;
    color: var(--danger-color);
    font-weight: 600;
}

.logout-icon {
    margin-right: 10px;
}