:root {
    /* Day Theme (Default) */
    --theme-bg: #ffffff;
    --theme-text: #1f2937;
    --theme-accent: #ff9aa2;
    --theme-accent-gradient: linear-gradient(135deg, #ff9aa2 0%, #ffb7b2 100%);
    --theme-card-bg: rgba(255, 255, 255, 0.8);
    --theme-glass-border: rgba(255, 255, 255, 0.4);
    --theme-nav-bg: rgba(255, 255, 255, 0.9);
    --theme-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.1);
    --theme-glow: none;
    --anim-float-display: block;
    --anim-drip-display: none;
}

/* Night Theme */
body.theme-night {
    --theme-bg: #0f172a;
    --theme-text: #f8fafc;
    --theme-accent: #ec4899;
    --theme-accent-gradient: linear-gradient(135deg, #ec4899 0%, #8b5cf6 100%);
    --theme-card-bg: rgba(30, 41, 59, 0.7);
    --theme-glass-border: rgba(255, 255, 255, 0.1);
    --theme-nav-bg: rgba(15, 23, 42, 0.9);
    --theme-shadow: 0 10px 40px -10px rgba(0, 0, 0, 0.5);
    --theme-glow: 0 0 15px rgba(236, 72, 153, 0.4);
    --anim-float-display: none;
    --anim-drip-display: none;
}

/* Summer / Heat Theme */
body.theme-summer {
    --theme-bg: #f0f9ff;
    --theme-text: #075985;
    --theme-accent: #0ea5e9;
    --theme-accent-gradient: linear-gradient(135deg, #0ea5e9 0%, #38bdf8 100%);
    --theme-card-bg: rgba(255, 255, 255, 0.6);
    --theme-glass-border: rgba(14, 165, 233, 0.2);
    --theme-nav-bg: rgba(240, 249, 255, 0.9);
    --theme-shadow: 0 10px 30px -10px rgba(14, 165, 233, 0.1);
    --theme-glow: none;
    --anim-float-display: none;
    --anim-drip-display: block;
}

/* Transitions */
body {
    background-color: var(--theme-bg);
    color: var(--theme-text);
    transition: background-color 0.6s ease, color 0.6s ease;
}

/* Components using variables */
.card, .glass-panel {
    background: var(--theme-card-bg);
    backdrop-filter: blur(10px);
    border: 1px solid var(--theme-glass-border);
    box-shadow: var(--theme-shadow);
}

.btn-primary {
    background: var(--theme-accent-gradient);
    box-shadow: var(--theme-glow);
}

/* Floating Bubbles Animation for Day */
.floating-elements {
    display: var(--anim-float-display);
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: -1;
    overflow: hidden;
}

.bubble {
    position: absolute;
    bottom: -100px;
    background: var(--theme-accent);
    opacity: 0.1;
    border-radius: 50%;
    animation: float 15s infinite ease-in;
}

@keyframes float {
    0% { transform: translateY(0) rotate(0deg); opacity: 0.1; }
    50% { opacity: 0.2; }
    100% { transform: translateY(-120vh) rotate(360deg); opacity: 0; }
}

/* Icy Drip Effect for Summer */
.dripping-elements {
    display: var(--anim-drip-display);
    position: fixed;
    top: 0;
    width: 100%;
    height: 20px;
    z-index: 100;
}

.drip {
    position: absolute;
    width: 4px;
    height: 20px;
    background: var(--theme-accent);
    border-radius: 0 0 4px 4px;
    animation: drip 2s infinite ease-in;
}

@keyframes drip {
    0% { height: 0; opacity: 1; }
    50% { height: 50px; opacity: 1; }
    100% { height: 100px; opacity: 0; transform: translateY(100vh); }
}

/* Theme Switcher Widget */
.theme-switcher-widget {
    position: fixed;
    bottom: 30px;
    left: 30px;
    z-index: 1000;
}

.theme-main-btn {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--theme-accent-gradient);
    border: none;
    color: white;
    font-size: 1.5rem;
    box-shadow: 0 10px 20px rgba(0,0,0,0.2);
    cursor: pointer;
    transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.theme-main-btn:hover {
    transform: scale(1.1) rotate(15deg);
}

.theme-menu {
    position: absolute;
    bottom: 80px;
    left: 0;
    width: 150px;
    padding: 10px;
    border-radius: 20px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    transform-origin: bottom left;
}

.theme-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 15px;
    border-radius: 12px;
    border: none;
    background: transparent;
    color: var(--theme-text);
    font-family: 'Quicksand', sans-serif;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s;
}

.theme-btn:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateX(5px);
}

.theme-btn.active {
    background: var(--theme-accent-gradient);
    color: white;
}

.theme-btn i {
    width: 20px;
}