/* === 液態玻璃動畫變數 === */
@property --angle-1 { syntax: "<angle>"; inherits: false; initial-value: -75deg; }
@property --angle-2 { syntax: "<angle>"; inherits: false; initial-value: -45deg; }

:root {
    /* 🌙 Dark Mode - 科技黑 */
    --color-background: #0F0F1B;
    --color-text-primary: #ffffff;
    --color-text-secondary: rgba(255, 255, 255, 0.7);
    --color-glass-bg: rgba(255, 255, 255, 0.03);
    --color-glass-border: rgba(255, 255, 255, 0.1);
    --color-glass-hover: rgba(255, 255, 255, 0.08);
    --color-input-bg: rgba(0, 0, 0, 0.4);
    --color-accent: #a7a7d1;
    --color-accent-hover: rgba(167, 167, 209, 0.2);
    --color-heart: #ff4757;
    
    /* 液態按鈕專屬變數 */
    --color-button-shadow-1: rgba(0, 0, 0, 0.05);
    --color-button-shadow-2: rgba(255, 255, 255, 0.5);
    --color-button-shadow-3: rgba(0, 0, 0, 0.2);
    --color-button-shadow-4: rgba(255, 255, 255, 0.2);
    --anim--hover-time: 400ms;
    --anim--hover-ease: cubic-bezier(0.25, 1, 0.5, 1);
    
    --sidebar-width: 260px;
}

body.light-mode {
    /* ☕ Light Mode - 溫暖拿鐵 */
    --color-background: #F7F4EF;
    --color-text-primary: #3E2723;
    --color-text-secondary: #795C54;
    --color-glass-bg: rgba(255, 255, 255, 0.6);
    --color-glass-border: rgba(111, 78, 55, 0.15);
    --color-glass-hover: rgba(255, 255, 255, 0.9);
    --color-input-bg: rgba(255, 255, 255, 0.8);
    --color-accent: #6F4E37;
    --color-accent-hover: rgba(111, 78, 55, 0.1);
    --color-heart: #D84315;

    /* 液態按鈕淺色變數 */
    --color-button-shadow-1: rgba(255, 255, 255, 0.8);
    --color-button-shadow-2: rgba(0, 0, 0, 0.1);
    --color-button-shadow-3: rgba(0, 0, 0, 0.05);
    --color-button-shadow-4: rgba(255, 255, 255, 0.5);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; overflow: hidden; font-family: "Inter", "Noto Sans TC", sans-serif; }

body {
    background-color: var(--color-background);
    background-image: url('../images/ai-tools-bg-black.png');
    background-repeat: no-repeat; background-position: center; background-size: cover;
    color: var(--color-text-primary);
    transition: background-color 0.5s ease, color 0.5s ease, background-image 0.5s ease;
}
body.light-mode { background-image: url('../images/ai-tools-bg-light.png'); }

#tsparticles { position: fixed; top: 0; left: 0; width: 100%; height: 100%; z-index: -1; pointer-events: none;}

/* === Animations === */
@keyframes fadeSlideUp {
    from { opacity: 0; transform: translateY(25px); }
    to { opacity: 1; transform: translateY(0); }
}
@keyframes heartBounce {
    0% { transform: scale(1); }
    40% { transform: scale(1.35); }
    100% { transform: scale(1); }
}
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

/* === App Layout === */
.app-container { display: flex; height: 100vh; width: 100vw; position: relative; z-index: 1; }

.glass-panel {
    background-color: var(--color-glass-bg);
    backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--color-glass-border);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.08);
    transition: background-color 0.4s ease, border-color 0.4s ease;
}

/* --- Sidebar --- */
.sidebar {
    width: var(--sidebar-width); flex-shrink: 0; display: flex; flex-direction: column;
    margin: 16px 0 16px 16px; border-radius: 20px; overflow-y: auto; padding: 24px 12px;
    transition: width 0.4s cubic-bezier(0.2, 0.8, 0.2, 1), margin 0.4s ease, opacity 0.3s ease;
    z-index: 100; scrollbar-width: none;
}
.sidebar::-webkit-scrollbar { display: none; }
.sidebar.collapsed-desktop { width: 0; margin: 0; padding: 0; opacity: 0; border: none; pointer-events: none; }

.nav-section-title {
    font-size: 0.75rem; color: var(--color-text-secondary); margin: 16px 0 8px 12px; font-weight: 600; letter-spacing: 0.5px;
}

.nav-btn {
    display: flex; align-items: center; gap: 12px; width: 100%; padding: 10px 12px; border: none; background: transparent;
    color: var(--color-text-secondary); font-size: 0.9rem; font-weight: 500; text-align: left; border-radius: 12px; cursor: pointer;
    transition: all 0.25s cubic-bezier(0.2, 0.8, 0.2, 1); margin-bottom: 4px;
}
.nav-btn svg { width: 18px; height: 18px; stroke: currentColor; fill: none; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; transition: transform 0.2s;}
.nav-btn:hover { background: var(--color-glass-hover); color: var(--color-text-primary); transform: translateX(4px); }
.nav-btn.active { background: var(--color-accent); color: #fff; font-weight: 600; transform: translateX(4px); box-shadow: 0 4px 12px rgba(0,0,0,0.1);}
body.light-mode .nav-btn.active { color: var(--color-bg-base); }

.sidebar-footer {
    margin-top: auto;
    padding-top: 20px;
    text-align: center;
    color: var(--color-text-secondary);
    font-size: 0.8rem;
}

/* --- Main Content Area --- */
.main-wrapper { flex: 1; display: flex; flex-direction: column; min-width: 0; }

/* --- Topbar --- */
.topbar {
    height: 68px; margin: 16px 16px 0 16px; border-radius: 20px;
    display: flex; align-items: center; justify-content: space-between;
    padding: 0 20px; gap: 24px; flex-shrink: 0; position: relative;
}

.brand-area { display: flex; align-items: center; gap: 12px; }
.hamburger-btn {
    display: flex; align-items: center; justify-content: center; background: transparent; border: none; color: var(--color-text-primary); 
    cursor: pointer; padding: 6px; border-radius: 8px; transition: all 0.2s; margin-left: -4px;
}
.hamburger-btn:hover { background: var(--color-accent-hover); }
.hamburger-btn svg { width: 22px; height: 22px; stroke: currentColor; stroke-width: 2; stroke-linecap: round; fill: none;}

.brand-avatar { width: 34px; height: 34px; border-radius: 50%; object-fit: cover; transition: transform 0.3s; box-shadow: 0 4px 10px rgba(0,0,0,0.2);}
.brand-area:hover .brand-avatar { transform: scale(1.05) rotate(-2deg); }
.brand-title { font-size: 1.1rem; font-weight: 700; color: var(--color-text-primary); letter-spacing: 0.5px;}

/* Search Area */
.search-container { flex: 1; max-width: 400px; position: relative; display: flex; align-items: center; }
.search-icon { position: absolute; left: 14px; top: 50%; transform: translateY(-50%); width: 16px; height: 16px; color: var(--color-text-secondary); pointer-events: none;}
#search-input {
    width: 100%; background: var(--color-input-bg); border: 1px solid var(--color-glass-border);
    border-radius: 99px; padding: 10px 36px 10px 40px; color: var(--color-text-primary);
    font-size: 0.9rem; outline: none; transition: all 0.3s cubic-bezier(0.2, 0.8, 0.2, 1); font-family: inherit;
}
#search-input:focus { border-color: var(--color-accent); width: 105%; box-shadow: 0 0 0 3px var(--color-accent-hover);}
#search-input::placeholder { color: var(--color-text-secondary); opacity: 0.7; }

.clear-btn {
    position: absolute; right: 12px; top: 50%; transform: translateY(-50%); background: none; border: none; color: var(--color-text-secondary);
    cursor: pointer; display: none; padding: 4px; font-size: 14px; transition: transform 0.2s;
}
.clear-btn:hover { color: var(--color-text-primary); transform: translateY(-50%) scale(1.2);}

.mobile-search-btn, .mobile-search-back { display: none; background: transparent; border: none; color: var(--color-text-primary); cursor: pointer; padding: 8px;}
.mobile-search-btn svg, .mobile-search-back svg { width: 20px; height: 20px; stroke: currentColor; fill: none; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round;}

.topbar-actions { display: flex; align-items: center; gap: 8px; }

/* 收藏狀態按鈕 */
.auth-btn {
    display: flex; align-items: center; gap: 8px; background: var(--color-input-bg);
    border: 1px solid var(--color-glass-border); padding: 6px 14px; border-radius: 99px;
    color: var(--color-text-primary); cursor: pointer; transition: all 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
    backdrop-filter: blur(12px);
}
.auth-btn:hover { background: var(--color-accent-hover); border-color: var(--color-accent); transform: translateY(-2px); box-shadow: 0 4px 10px rgba(0,0,0,0.1); }
.auth-btn:disabled { cursor: wait; opacity: 0.72; transform: none; }
.auth-btn.is-loading { pointer-events: none; }
.auth-btn img { width: 22px; height: 22px; border-radius: 50%; display: none; object-fit: cover; }
.auth-btn span { font-size: 0.9rem; font-weight: 600; white-space: nowrap; }

.icon-btn {
    background: var(--color-input-bg); border: 1px solid var(--color-glass-border);
    width: 38px; height: 38px; border-radius: 50%; display: flex; align-items: center; justify-content: center;
    color: var(--color-text-primary); cursor: pointer; transition: all 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
}
.icon-btn:hover { background: var(--color-accent-hover); border-color: var(--color-accent); transform: translateY(-2px); box-shadow: 0 4px 10px rgba(0,0,0,0.1); }
.icon-btn svg { width: 18px; height: 18px; stroke: currentColor; fill: none; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round;}

/* --- Content Area --- */
.content-area { flex: 1; overflow-y: auto; padding: 24px 16px; scroll-behavior: smooth; display: flex; flex-direction: column; }
.content-area::-webkit-scrollbar { width: 6px; }
.content-area::-webkit-scrollbar-track { background: transparent; }
.content-area::-webkit-scrollbar-thumb { background: var(--color-glass-border); border-radius: 3px; }

.section-header { margin-bottom: 24px; padding-left: 4px;}
.section-title { font-size: 1.35rem; font-weight: 700; display: flex; align-items: center; gap: 10px; color: var(--color-text-primary);}
.section-title svg { width: 24px; height: 24px; stroke: currentColor; fill: none; stroke-width: 2;}

/* --- Tool Grid & Cards --- */
.tool-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(310px, 1fr));
    gap: 20px; padding-bottom: 20px; flex: 1; align-content: start;
}

.loading-message {
    text-align: center;
    grid-column: 1 / -1;
    margin-top: 40px;
    font-weight: 400;
    color: var(--color-text-secondary);
}

.tool-card {
    background: var(--color-glass-bg); border: 1px solid var(--color-glass-border);
    border-radius: 20px; padding: 20px; display: flex; flex-direction: column; gap: 12px;
    position: relative; transition: border-color 0.3s ease, background 0.3s ease, transform 0.3s cubic-bezier(0.2, 0.8, 0.2, 1), box-shadow 0.3s ease;
    opacity: 0; backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
    content-visibility: auto; contain-intrinsic-size: 180px;
}
.tool-card.hidden { display: none !important; }
.tool-card:hover { 
    border-color: var(--color-accent); background: var(--color-glass-hover);
    transform: translateY(-6px); box-shadow: 0 12px 30px rgba(0,0,0,0.15);
}

.card-header { display: flex; align-items: flex-start; gap: 12px; padding-right: 28px;}

.card-icon {
    color: var(--color-accent); flex-shrink: 0; display: flex; align-items: center; justify-content: center;
    background: var(--color-input-bg); padding: 8px; border-radius: 12px; border: 1px solid var(--color-glass-border);
    transition: transform 0.3s cubic-bezier(0.2, 0.8, 0.2, 1);
}
.card-icon svg { width: 22px; height: 22px; stroke: currentColor; fill: none; stroke-width: 2; stroke-linejoin: round; stroke-linecap: round;}
.tool-card:hover .card-icon { transform: scale(1.1) rotate(-3deg); }

.tool-name { font-size: 1.1rem; font-weight: 700; line-height: 1.35; margin-top: 2px; color: var(--color-text-primary);}

.tool-description { 
    font-size: 0.9rem; color: var(--color-text-secondary); line-height: 1.6;
    display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
    margin-bottom: auto; min-height: 2.8rem; 
}

/* Heart Favorite Button */
.fav-btn {
    position: absolute; top: 20px; right: 20px; background: transparent; border: none; cursor: pointer;
    color: var(--color-text-secondary); padding: 4px; border-radius: 50%;
    transition: all 0.2s ease; display: flex; align-items: center; justify-content: center; opacity: 0.4;
    z-index: 10;
}
.tool-card:hover .fav-btn { opacity: 1; }
.fav-btn svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 2; transition: all 0.2s;}
.fav-btn:hover { color: var(--color-heart); background: rgba(255, 71, 87, 0.1);}
.fav-btn.active { color: var(--color-heart); opacity: 1;}
.fav-btn.active svg { fill: currentColor; stroke: currentColor; animation: heartBounce 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275); }

/* === 🏆 完美回歸：液態玻璃按鈕 (強制置左、不拉長) === */
.card-buttons { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 14px; justify-content: flex-start; }
.button-wrap {
    flex: 0 0 calc(50% - 5px); min-width: 0; position: relative; z-index: 2; border-radius: 999vw;
    background: transparent; pointer-events: none;
}
.button-wrap button {
    --border-width: 2px; all: unset; cursor: pointer; position: relative;
    pointer-events: auto; z-index: 3;
    background: linear-gradient(-75deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.15), rgba(255, 255, 255, 0.05));
    border-radius: 999vw; box-shadow: inset 0 0.125em 0.125em var(--color-button-shadow-1), inset 0 -0.125em 0.125em var(--color-button-shadow-2), 0 0.25em 0.125em -0.125em var(--color-button-shadow-3), 0 0 0.1em 0.25em inset var(--color-button-shadow-4);
    backdrop-filter: blur(4px); -webkit-backdrop-filter: blur(4px);
    transition: transform var(--anim--hover-time) var(--anim--hover-ease);
    display: flex; justify-content: center; width: 100%; height: 100%;
}
body.light-mode .button-wrap button { background: linear-gradient(-75deg, rgba(0, 0, 0, 0.02), rgba(0, 0, 0, 0.05), rgba(0, 0, 0, 0.02)); }

.button-wrap button:hover { transform: scale(0.97); }
.button-wrap button:active { transform: scale(0.94); background: linear-gradient(-75deg, rgba(150, 120, 255, 0.1), rgba(180, 150, 255, 0.3), rgba(150, 120, 255, 0.1)); }

.button-wrap button span {
    position: relative; display: flex; align-items: center; justify-content: center;
    font-weight: 500; font-size: 0.85rem; line-height: 1.25;
    color: var(--color-text-primary); text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
    padding: 0.7em 0.8em; width: 100%; text-align: center;
    white-space: normal; word-break: keep-all;
}
body.light-mode .button-wrap button span { text-shadow: none; font-weight: 600;}

.button-wrap button span::after {
    content: ""; display: block; position: absolute; z-index: 1;
    width: calc(100% - var(--border-width)); height: calc(100% - var(--border-width));
    top: calc(0% + var(--border-width) / 2); left: calc(0% + var(--border-width) / 2);
    box-sizing: border-box; border-radius: 999vw; overflow: clip;
    background: linear-gradient(var(--angle-2), rgba(255, 255, 255, 0) 0%, rgba(255, 255, 255, 0.4) 40% 50%, rgba(255, 255, 255, 0) 55%);
    mix-blend-mode: screen; pointer-events: none; background-size: 200% 200%; background-position: 0% 50%;
    transition: background-position calc(var(--anim--hover-time) * 1.25) var(--anim--hover-ease), --angle-2 calc(var(--anim--hover-time) * 1.25) var(--anim--hover-ease);
}
body.light-mode .button-wrap button span::after { mix-blend-mode: normal; background: linear-gradient(var(--angle-2), rgba(255, 255, 255, 0) 0%, rgba(255, 255, 255, 0.6) 40% 50%, rgba(255, 255, 255, 0) 55%); }
.button-wrap button:hover span::after { background-position: 25% 50%; }

.button-wrap button::after {
    content: ""; position: absolute; z-index: 1; inset: 0; border-radius: 999vw;
    width: calc(100% + var(--border-width)); height: calc(100% + var(--border-width));
    top: calc(0% - var(--border-width) / 2); left: calc(0% - var(--border-width) / 2);
    padding: var(--border-width); box-sizing: border-box;
    background: conic-gradient(from var(--angle-1) at 50% 50%, rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0) 5% 40%, rgba(0, 0, 0, 0.5) 50%, rgba(0, 0, 0, 0) 60% 95%, rgba(0, 0, 0, 0.5)), linear-gradient(180deg, rgba(255, 255, 255, 0.5), rgba(255, 255, 255, 0.5));
    mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0); mask-composite: exclude;
    transition: all var(--anim--hover-time) var(--anim--hover-ease), --angle-1 500ms ease;
    box-shadow: inset 0 0 0 calc(var(--border-width) / 2) rgba(255, 255, 255, 0.5);
}
body.light-mode .button-wrap button::after { background: conic-gradient(from var(--angle-1) at 50% 50%, rgba(111, 78, 55, 0.2), rgba(0, 0, 0, 0) 5% 40%, rgba(111, 78, 55, 0.2) 50%, rgba(0, 0, 0, 0) 60% 95%, rgba(111, 78, 55, 0.2)), linear-gradient(180deg, rgba(0, 0, 0, 0.1), rgba(0, 0, 0, 0.1)); box-shadow: inset 0 0 0 calc(var(--border-width) / 2) rgba(111, 78, 55, 0.2);}
.button-wrap button:hover::after { --angle-1: -125deg; }

@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
    }
    #tsparticles { display: none; }
}

/* --- Footer Info Area --- */
.main-footer {
    margin-top: 32px; padding: 24px; border-top: 1px solid var(--color-glass-border);
    color: var(--color-text-secondary); font-size: 0.9rem; line-height: 1.6;
    display: flex; flex-direction: column; gap: 12px; border-radius: 20px; margin-bottom: 20px;
    animation: fadeIn 1s ease forwards;
}
.is-hidden { display: none !important; }
.footer-item { display: flex; align-items: flex-start; gap: 10px; }
.footer-item svg { width: 18px; height: 18px; flex-shrink: 0; margin-top: 2px; stroke: var(--color-text-primary); fill: none; stroke-width: 2;}
.footer-link { color: var(--color-text-primary); text-decoration: underline; text-decoration-color: var(--color-glass-border); transition: all 0.2s;}
.footer-link:hover { text-decoration-color: var(--color-accent); color: var(--color-accent);}

/* --- Mobile Responsive --- */
.sidebar-overlay {
    display: none; position: fixed; inset: 0; background: rgba(0,0,0,0.6);
    backdrop-filter: blur(4px); z-index: 95; opacity: 0; transition: opacity 0.3s;
}

@media (max-width: 900px) { .brand-title { display: none; } }

@media (max-width: 768px) {
    .sidebar {
        position: fixed; top: 0; left: 0; height: calc(100vh - 24px);
        transform: translateX(-120%); margin: 12px; width: 260px;
        background: var(--color-background); border: 1px solid var(--color-glass-border); box-shadow: 4px 0 24px rgba(0,0,0,0.3);
    }
    .sidebar.active { transform: translateX(0); }
    .sidebar-overlay.active { display: block; opacity: 1; }
    
    .topbar { margin: 12px; height: 60px; padding: 0 16px; gap: 12px; }
    
    .search-container {
        display: none; position: absolute; inset: 0; padding: 0 16px;
        background: var(--color-background); border-radius: 20px; border: 1px solid var(--color-glass-border);
        z-index: 10; align-items: center; gap: 10px;
    }
    .search-container.mobile-active { display: flex; animation: fadeIn 0.2s ease;}
    .search-container .search-icon { left: 44px; }
    #search-input { padding-left: 36px; background: transparent; border: none; box-shadow: none !important;}
    
    .mobile-search-btn { display: flex; align-items: center; justify-content: center; margin-left: auto; background: transparent; border: none; color: var(--color-text-primary); cursor: pointer; padding: 8px;}
    .mobile-search-back { display: block; padding: 4px; flex-shrink: 0; background: transparent; border: none; color: var(--color-text-primary); cursor: pointer;}
    .mobile-search-btn svg, .mobile-search-back svg { width: 22px; height: 22px; stroke: currentColor; fill: none; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round;}
    .clear-btn { right: 16px; } 
    
    .content-area { padding: 16px 12px; }
    .tool-grid { grid-template-columns: 1fr; gap: 16px; }
}