/* CSS Variables for Theming */
:root {
    --background-color: #1a1a1a;
    --text-color: #fff;
    --secondary-text-color: #e0e0e0;
    --button-bg-start: rgba(255, 255, 255, 0.08);
    --button-bg-end: rgba(255, 255, 255, 0.04);
    --button-border: rgba(255, 255, 255, 0.3);
    --button-hover-bg-start: rgba(255, 255, 255, 0.12);
    --button-hover-bg-end: rgba(255, 255, 255, 0.08);
    --button-hover-border: rgba(255, 255, 255, 0.6);
    --popup-bg: linear-gradient(to bottom, rgba(0, 0, 0, 0.95), rgba(0, 0, 0, 0.9));
    --sidebar-bg: linear-gradient(to bottom, rgba(0, 0, 0, 0.95), rgba(0, 0, 0, 0.9));
    --input-bg-start: rgba(255, 255, 255, 0.05);
    --input-bg-end: rgba(255, 255, 255, 0.02);
    --input-border: rgba(255, 255, 255, 0.3);
    --shadow-color: rgba(0, 0, 0, 0.8);
    --text-shadow: 0 2px 4px rgba(0, 0, 0, 0.5);
    --gradient-text: linear-gradient(90deg, #ffffff, #e0e0e0, #a0a0a0, #e0e0e0, #ffffff);
}

.light-mode {
    --background-color: #f5f5f5;
    --text-color: #333;
    --secondary-text-color: #555;
    --button-bg-start: rgba(0, 0, 0, 0.08);
    --button-bg-end: rgba(0, 0, 0, 0.04);
    --button-border: rgba(0, 0, 0, 0.3);
    --button-hover-bg-start: rgba(0, 0, 0, 0.12);
    --button-hover-bg-end: rgba(0, 0, 0, 0.08);
    --button-hover-border: rgba(0, 0, 0, 0.6);
    --popup-bg: linear-gradient(to bottom, rgba(255, 255, 255, 0.95), rgba(255, 255, 255, 0.9));
    --sidebar-bg: linear-gradient(to bottom, rgba(255, 255, 255, 0.95), rgba(255, 255, 255, 0.9));
    --input-bg-start: rgba(0, 0, 0, 0.05);
    --input-bg-end: rgba(0, 0, 0, 0.02);
    --input-border: rgba(0, 0, 0, 0.3);
    --shadow-color: rgba(0, 0, 0, 0.2);
    --text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    --gradient-text: linear-gradient(90deg, #333333, #555555, #777777, #555555, #333333);
}

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

body {
    font-family: "Cabin", sans-serif;
    font-optical-sizing: auto;
    font-weight: 400;
    font-style: normal;
    font-variation-settings: "wdth" 100;
    color: var(--text-color);
    background: var(--background-color);
    overflow-x: hidden;
    position: relative;
}

/* Common Button Styles */
button {
    background: linear-gradient(to right, var(--button-bg-start), var(--button-bg-end));
    border: 1px solid var(--button-border);
    color: var(--text-color);
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.3s, box-shadow 0.3s, border-color 0.3s, transform 0.2s;
    box-shadow: 0 2px 8px var(--shadow-color);
    font-family: "Cabin", sans-serif;
    font-optical-sizing: auto;
    font-weight: 400;
    font-style: normal;
    font-variation-settings: "wdth" 100;
    padding: 0.5rem 1rem;
}

button:hover {
    background: linear-gradient(to right, var(--button-hover-bg-start), var(--button-hover-bg-end));
    box-shadow: 0 4px 12px var(--shadow-color);
    border-color: var(--button-hover-border);
    transform: translateY(-2px);
}

/* Video Background */
.video-background {
    position: fixed;
    top: -15%;
    left: 0;
    width: 100%;
    height: 130%;
    z-index: -1;
    overflow: hidden;
}

#youtube-video {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: filter 0.3s ease;
}

/* Reminder Overlay */
.reminder-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
}

.reminder-overlay.show {
    opacity: 1;
    visibility: visible;
}

/* Tutorial Popup */
.tutorial-popup {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0);
    background: var(--popup-bg);
    backdrop-filter: blur(10px);
    border-radius: 10px;
    box-shadow: 0 8px 30px var(--shadow-color);
    z-index: 1005;
    max-width: 600px;
    width: 95%;
    transition: transform 0.4s ease, visibility 0.4s ease;
    visibility: hidden;
}

.tutorial-popup.show {
    transform: translate(-50%, -50%) scale(1);
    visibility: visible;
}

.tutorial-content {
    padding: 2rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

.tutorial-content h2 {
    font-family: "Doto", sans-serif;
    font-optical-sizing: auto;
    font-weight: 700;
    font-style: normal;
    font-variation-settings: "ROND" 0;
    font-size: 1.8rem;
    text-align: center;
    animation: gradientFlow 3s infinite linear;
    background: var(--gradient-text);
    background-size: 200%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.tutorial-content p {
    font-size: 1rem;
    text-align: left;
    color: var(--secondary-text-color);
    text-shadow: var(--text-shadow);
}

.start-using-btn {
    width: auto;
}

/* Header */
header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
    z-index: 1002;
}

.logo {
    font-family: "Doto", sans-serif;
    font-optical-sizing: auto;
    font-style: normal;
    font-variation-settings: "ROND" 0;
    font-size: 2.2rem;
    text-shadow: 0 4px 12px var(--shadow-color);
    animation: gradientFlow 3s infinite linear, fontWeightCycle 9s infinite ease-in-out;
    background: var(--gradient-text);
    background-size: 200%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.controls {
    display: flex;
    gap: 1.2rem;
}

.fullscreen-btn, .settings-btn {
    background: none;
    border: none;
    color: var(--text-color);
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: transform 0.2s, color 0.3s;
    text-shadow: 0 0 10px var(--shadow-color);
}

.fullscreen-btn:hover, .settings-btn:hover {
    transform: scale(1.1);
    color: var(--secondary-text-color);
}

.material-symbols-outlined {
    font-variation-settings: 'FILL' 0, 'wght' 400, 'GRAD' 0, 'opsz' 24;
}

/* Settings Sidebar */
.settings-sidebar {
    position: fixed;
    top: 0;
    right: -300px;
    width: 300px;
    height: 100%;
    background: var(--sidebar-bg);
    backdrop-filter: blur(10px);
    padding: 1.5rem;
    z-index: 1003;
    transition: right 0.4s ease;
    box-shadow: -8px 0 20px var(--shadow-color);
}

.settings-sidebar.open {
    right: 0;
}

.settings-scroll {
    max-height: calc(100% - 3rem);
    overflow-y: auto;
    scrollbar-width: thin;
    scrollbar-color: var(--button-border) var(--background-color);
}

.settings-scroll::-webkit-scrollbar {
    width: 6px;
}

.settings-scroll::-webkit-scrollbar-track {
    background: var(--background-color);
}

.settings-scroll::-webkit-scrollbar-thumb {
    background: var(--button-border);
    border-radius: 3px;
}

.settings-scroll::-webkit-scrollbar-thumb:hover {
    background: var(--button-hover-border);
}

.settings-sidebar h2 {
    font-weight: 700;
    font-variation-settings: "wdth" 125;
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    animation: gradientFlow 3s infinite linear;
    background: var(--gradient-text);
    background-size: 200%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.close-sidebar {
    position: absolute;
    top: 1.2rem;
    right: 1.2rem;
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.5rem;
    cursor: pointer;
    transition: transform 0.3s, color 0.3s, text-shadow 0.3s;
}

.close-sidebar:hover {
    transform: rotate(90deg);
    color: var(--secondary-text-color);
    text-shadow: 0 0 8px var(--shadow-color);
}

.settings-form {
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
}

.settings-group {
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

.settings-group h3 {
    font-weight: 600;
    font-variation-settings: "wdth" 125;
    font-size: 1.2rem;
    margin-bottom: 0.8rem;
    animation: gradientFlow 3s infinite linear;
    background: var(--gradient-text);
    background-size: 200%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.settings-form label {
    font-size: 0.95rem;
    color: var(--secondary-text-color);
    text-shadow: var(--text-shadow);
    transition: color 0.3s;
}

.settings-form label:hover {
    color: var(--text-color);
}

.settings-form select, .settings-form input[type="range"] {
    padding: 0.5rem;
    border: 1px solid var(--input-border);
    background: linear-gradient(to right, var(--input-bg-start), var(--input-bg-end));
    color: var(--text-color);
    border-radius: 6px;
    transition: border-color 0.3s, background 0.3s, box-shadow 0.3s;
    box-shadow: 0 2px 8px var(--shadow-color);
}

.settings-form select:hover, .settings-form input[type="range"]:hover {
    border-color: var(--button-hover-border);
    background: linear-gradient(to right, var(--input-bg-start), var(--input-bg-end));
    box-shadow: 0 4px 12px var(--shadow-color);
}

.settings-form select:focus, .settings-form input[type="range"]:focus {
    border-color: var(--button-hover-border);
    background: linear-gradient(to right, var(--input-bg-start), var(--input-bg-end));
    box-shadow: 0 4px 16px var(--shadow-color);
    outline: none;
}

.settings-form select option {
    background: var(--background-color);
    color: var(--text-color);
}

.volume-container {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.mute-indicator {
    font-size: 0.9rem;
    opacity: 0;
    transition: opacity 0.3s ease;
    text-shadow: var(--text-shadow);
}

.settings-form input[type="range"] {
    -webkit-appearance: none;
    height: 5px;
    border-radius: 5px;
    width: 100%;
}

.settings-form input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 14px;
    height: 14px;
    background: linear-gradient(to bottom, var(--text-color), var(--secondary-text-color));
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 2px 8px var(--shadow-color);
    transition: transform 0.2s, box-shadow 0.2s;
}

.settings-form input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.15);
    box-shadow: 0 4px 12px var(--shadow-color);
}

.video-controls, .timer-controls {
    display: flex;
    gap: 0.5rem;
}

.video-controls button, .timer-controls button, #test-reminder {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 0.8rem;
}

.timer-display {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--secondary-text-color);
    text-shadow: var(--text-shadow);
    margin-top: 0.8rem;
}

.timer-display label {
    margin-bottom: 0;
}

#timer {
    font-weight: 600;
    font-variation-settings: "wdth" 125;
    font-size: 1.2rem;
    animation: gradientFlow 3s infinite linear;
    background: var(--gradient-text);
    background-size: 200%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.toggle {
    display: flex;
    align-items: center;
    gap: 0.8rem;
    margin-bottom: 0.8rem;
}

.toggle input {
    width: 36px;
    height: 18px;
    -webkit-appearance: none;
    background: linear-gradient(to right, var(--background-color), var(--secondary-text-color));
    border: 1px solid var(--text-color);
    border-radius: 9px;
    position: relative;
    cursor: pointer;
    transition: background 0.3s, border-color 0.3s, box-shadow 0.3s;
    box-shadow: inset 0 2px 4px var(--shadow-color);
}

.toggle input:checked {
    background: linear-gradient(to right, var(--text-color), var(--secondary-text-color));
    border-color: var(--background-color);
    box-shadow: inset 0 2px 4px var(--shadow-color);
}

.toggle input::before {
    content: '';
    position: absolute;
    width: 14px;
    height: 14px;
    background: var(--text-color);
    border-radius: 50%;
    top: 2px;
    left: 2px;
    transition: transform 0.3s, background 0.3s, box-shadow 0.3s;
    box-shadow: 0 2px 4px var(--shadow-color);
}

.toggle input:checked::before {
    transform: translateX(18px);
    background: var(--background-color);
    box-shadow: 0 2px 4px var(--shadow-color);
}

.toggle .mode-icon {
    font-size: 1.2rem;
}

.reminder-options {
    margin-top: 0.8rem;
    display: flex;
    flex-direction: column;
    gap: 0.8rem;
}

/* Reminder Popup */
.reminder-popup {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%) scale(0);
    background: var(--popup-bg);
    backdrop-filter: blur(10px);
    padding: 1.5rem;
    border-radius: 10px;
    box-shadow: 0 8px 30px var(--shadow-color);
    text-align: center;
    z-index: 1004;
    transition: transform 0.4s ease;
    visibility: hidden;
}

.reminder-popup.show {
    transform: translate(-50%, -50%) scale(1);
    visibility: visible;
}

.reminder-popup p {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    text-shadow: var(--text-shadow);
    animation: gradientFlow 3s infinite linear;
    background: var(--gradient-text);
    background-size: 200%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.close-popup {
    padding: 0.5rem 1rem;
}

/* Reminder Indicator */
.reminder-indicator {
    position: fixed;
    bottom: 0.8rem;
    left: 0.8rem;
    background: var(--popup-bg);
    backdrop-filter: blur(8px);
    padding: 0.4rem 0.7rem;
    border-radius: 5px;
    color: var(--text-color);
    font-size: 0.75rem;
    box-shadow: 0 4px 12px var(--shadow-color);
    transition: opacity 0.4s ease, transform 0.4s ease;
    opacity: 0;
    transform: translateY(8px);
}

.reminder-indicator.active {
    opacity: 1;
    transform: translateY(0);
}

#reminder-status {
    font-weight: 600;
    font-variation-settings: "wdth" 125;
    animation: gradientFlow 3s infinite linear;
    background: var(--gradient-text);
    background-size: 200%;
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

/* Animations */
@keyframes gradientFlow {
    0% { background-position: 0%; }
    100% { background-position: 200%; }
}

@keyframes fontWeightCycle {
    0% { font-weight: 100; }
    33% { font-weight: 400; }
    66% { font-weight: 700; }
    100% { font-weight: 100; }
}

/* Responsive Design */
@media (max-width: 768px) {
    .settings-sidebar {
        width: 100%;
        right: -100%;
    }

    .settings-sidebar.open {
        right: 0;
    }

    .logo {
        font-size: 1.8rem;
    }

    .controls button {
        width: 36px;
        height: 36px;
    }

    .reminder-indicator {
        font-size: 0.7rem;
        padding: 0.3rem 0.6rem;
    }

    .reminder-popup p {
        font-size: 1.1rem;
    }

    .tutorial-popup {
        max-width: 90%;
    }

    .tutorial-content h2 {
        font-size: 1.6rem;
    }

    .tutorial-content p {
        font-size: 0.9rem;
    }

    #timer {
        font-size: 1rem;
    }
}